Search Results

Search found 31578 results on 1264 pages for 'javascript functions'.

Page 17/1264 | < Previous Page | 13 14 15 16 17 18 19 20 21 22 23 24  | Next Page >

• How can I serialize functions using JSON or some other serialization library?

  - by Oragamster

  I am trying to create a program that uses javascript to write a simple textadventure that I can then post on my blog and run on my iphone. I have run into a problem though. I was trying to make it so that my program would save it's state into cookies using JSON to convert it into strings and then post it into a cookie but then I realised that I couldn't serialize the functions that are on my item object. I was trying to make it so that my item would have an associative array that would contain the name of the use as the key and the function as the value. This worked well untill I tried to serialize it. I learned that I could create a JSON like serialization for functions by storing the body into a string and using escape charectors for the double quotes but for some reason I was unable to make my cookie with the function as the string stored. When I posted the cookie and then tried to get it back the string wasn't there. My code and the over all project are on my site if you want to look at that, though my full code including the item actions are not posted yet.

  Read the article

• Monitoring Html Element CSS Changes in JavaScript

  - by Rick Strahl

  [ updated Feb 15, 2011: Added event unbinding to avoid unintended recursion ] Here's a scenario I've run into on a few occasions: I need to be able to monitor certain CSS properties on an HTML element and know when that CSS element changes. For example, I have a some HTML element behavior plugins like a drop shadow that attaches to any HTML element, but I then need to be able to automatically keep the shadow in sync with the window if the  element dragged around the window or moved via code. Unfortunately there's no move event for HTML elements so you can't tell when it's location changes. So I've been looking around for some way to keep track of the element and a specific CSS property, but no luck. I suspect there's nothing native to do this so the only way I could think of is to use a timer and poll rather frequently for the property. I ended up with a generic jQuery plugin that looks like this: (function($){ $.fn.watch = function (props, func, interval, id) { /// <summary> /// Allows you to monitor changes in a specific /// CSS property of an element by polling the value. /// when the value changes a function is called. /// The function called is called in the context /// of the selected element (ie. this) /// </summary> /// <param name="prop" type="String">CSS Properties to watch sep. by commas</param> /// <param name="func" type="Function"> /// Function called when the value has changed. /// </param> /// <param name="interval" type="Number"> /// Optional interval for browsers that don't support DOMAttrModified or propertychange events. /// Determines the interval used for setInterval calls. /// </param> /// <param name="id" type="String">A unique ID that identifies this watch instance on this element</param> /// <returns type="jQuery" /> if (!interval) interval = 200; if (!id) id = "_watcher"; return this.each(function () { var _t = this; var el$ = $(this); var fnc = function () { __watcher.call(_t, id) }; var itId = null; var data = { id: id, props: props.split(","), func: func, vals: [props.split(",").length], fnc: fnc, origProps: props, interval: interval }; $.each(data.props, function (i) { data.vals[i] = el$.css(data.props[i]); }); el$.data(id, data); hookChange(el$, id, data.fnc); }); function hookChange(el$, id, fnc) { el$.each(function () { var el = $(this); if (typeof (el.get(0).onpropertychange) == "object") el.bind("propertychange." + id, fnc); else if ($.browser.mozilla) el.bind("DOMAttrModified." + id, fnc); else itId = setInterval(fnc, interval); }); } function __watcher(id) { var el$ = $(this); var w = el$.data(id); if (!w) return; var _t = this; if (!w.func) return; // must unbind or else unwanted recursion may occur el$.unwatch(id); var changed = false; var i = 0; for (i; i < w.props.length; i++) { var newVal = el$.css(w.props[i]); if (w.vals[i] != newVal) { w.vals[i] = newVal; changed = true; break; } } if (changed) w.func.call(_t, w, i); // rebind event hookChange(el$, id, w.fnc); } } $.fn.unwatch = function (id) { this.each(function () { var el = $(this); var fnc = el.data(id).fnc; try { if (typeof (this.onpropertychange) == "object") el.unbind("propertychange." + id, fnc); else if ($.browser.mozilla) el.unbind("DOMAttrModified." + id, fnc); else clearInterval(id); } // ignore if element was already unbound catch (e) { } }); return this; } })(jQuery); With this I can now monitor movement by monitoring say the top CSS property of the element. The following code creates a box and uses the draggable (jquery.ui) plugin and a couple of custom plugins that center and create a shadow. Here's how I can set this up with the watcher: $("#box") .draggable() .centerInClient() .shadow() .watch("top", function() { $(this).shadow(); },70,"_shadow"); ... $("#box") .unwatch("_shadow") .shadow("remove"); This code basically sets up the window to be draggable and initially centered and then a shadow is added. The .watch() call then assigns a CSS property to monitor (top in this case) and a function to call in response. The component now sets up a setInterval call and keeps on pinging this property every time. When the top value changes the supplied function is called. While this works and I can now drag my window around with the shadow following suit it's not perfect by a long shot. The shadow move is delayed and so drags behind the window, but using a higher timer value is not appropriate either as the UI starts getting jumpy if the timer's set with too small of an increment. This sort of monitor can be useful for other things as well where operations are maybe not quite as time critical as a UI operation taking place. Can anybody see a better a better way of capturing movement of an element on the page?© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  JavaScript  jQuery  

  Read the article

• Getting Started with TypeScript – Classes, Static Types and Interfaces

  - by dwahlin

  I had the opportunity to speak on different JavaScript topics at DevConnections in Las Vegas this fall and heard a lot of interesting comments about JavaScript as I talked with people. The most frequent comment I heard from people was, “I guess it’s time to start learning JavaScript”. Yep – if you don’t already know JavaScript then it’s time to learn it. As HTML5 becomes more and more popular the amount of JavaScript code written will definitely increase. After all, many of the HTML5 features available in browsers have little to do with “tags” and more to do with JavaScript (web workers, web sockets, canvas, local storage, etc.). As the amount of JavaScript code being used in applications increases, it’s more important than ever to structure the code in a way that’s maintainable and easy to debug. While JavaScript patterns can certainly be used (check out my previous posts on the subject or my course on Pluralsight.com), several alternatives have come onto the scene such as CoffeeScript, Dart and TypeScript. In this post I’ll describe some of the features TypeScript offers and the benefits that they can potentially offer enterprise-scale JavaScript applications. It’s important to note that while TypeScript has several great features, it’s definitely not for everyone or every project especially given how new it is. The goal of this post isn’t to convince you to use TypeScript instead of standard JavaScript….I’m a big fan of JavaScript. Instead, I’ll present several TypeScript features and let you make the decision as to whether TypeScript is a good fit for your applications. TypeScript Overview Here’s the official definition of TypeScript from the http://typescriptlang.org site: “TypeScript is a language for application-scale JavaScript development. TypeScript is a typed superset of JavaScript that compiles to plain JavaScript. Any browser. Any host. Any OS. Open Source.” TypeScript was created by Anders Hejlsberg (the creator of the C# language) and his team at Microsoft. To sum it up, TypeScript is a new language that can be compiled to JavaScript much like alternatives such as CoffeeScript or Dart. It isn’t a stand-alone language that’s completely separate from JavaScript’s roots though. It’s a superset of JavaScript which means that standard JavaScript code can be placed in a TypeScript file (a file with a .ts extension) and used directly. That’s a very important point/feature of the language since it means you can use existing code and frameworks with TypeScript without having to do major code conversions to make it all work. Once a TypeScript file is saved it can be compiled to JavaScript using TypeScript’s tsc.exe compiler tool or by using a variety of editors/tools. TypeScript offers several key features. First, it provides built-in type support meaning that you define variables and function parameters as being “string”, “number”, “bool”, and more to avoid incorrect types being assigned to variables or passed to functions. Second, TypeScript provides a way to write modular code by directly supporting class and module definitions and it even provides support for custom interfaces that can be used to drive consistency. Finally, TypeScript integrates with several different tools such as Visual Studio, Sublime Text, Emacs, and Vi to provide syntax highlighting, code help, build support, and more depending on the editor. Find out more about editor support at http://www.typescriptlang.org/#Download. TypeScript can also be used with existing JavaScript frameworks such as Node.js, jQuery, and others and even catch type issues and provide enhanced code help. Special “declaration” files that have a d.ts extension are available for Node.js, jQuery, and other libraries out-of-the-box. Visit http://typescript.codeplex.com/SourceControl/changeset/view/fe3bc0bfce1f#samples%2fjquery%2fjquery.d.ts for an example of a jQuery TypeScript declaration file that can be used with tools such as Visual Studio 2012 to provide additional code help and ensure that a string isn’t passed to a parameter that expects a number. Although declaration files certainly aren’t required, TypeScript’s support for declaration files makes it easier to catch issues upfront while working with existing libraries such as jQuery. In the future I expect TypeScript declaration files will be released for different HTML5 APIs such as canvas, local storage, and others as well as some of the more popular JavaScript libraries and frameworks. Getting Started with TypeScript To get started learning TypeScript visit the TypeScript Playground available at http://www.typescriptlang.org. Using the playground editor you can experiment with TypeScript code, get code help as you type, and see the JavaScript that TypeScript generates once it’s compiled. Here’s an example of the TypeScript playground in action:   One of the first things that may stand out to you about the code shown above is that classes can be defined in TypeScript. This makes it easy to group related variables and functions into a container which helps tremendously with re-use and maintainability especially in enterprise-scale JavaScript applications. While you can certainly simulate classes using JavaScript patterns (note that ECMAScript 6 will support classes directly), TypeScript makes it quite easy especially if you come from an object-oriented programming background. An example of the Greeter class shown in the TypeScript Playground is shown next: class Greeter { greeting: string; constructor (message: string) { this.greeting = message; } greet() { return "Hello, " + this.greeting; } } Looking through the code you’ll notice that static types can be defined on variables and parameters such as greeting: string, that constructors can be defined, and that functions can be defined such as greet(). The ability to define static types is a key feature of TypeScript (and where its name comes from) that can help identify bugs upfront before even running the code. Many types are supported including primitive types like string, number, bool, undefined, and null as well as object literals and more complex types such as HTMLInputElement (for an <input> tag). Custom types can be defined as well. The JavaScript output by compiling the TypeScript Greeter class (using an editor like Visual Studio, Sublime Text, or the tsc.exe compiler) is shown next: var Greeter = (function () { function Greeter(message) { this.greeting = message; } Greeter.prototype.greet = function () { return "Hello, " + this.greeting; }; return Greeter; })(); Notice that the code is using JavaScript prototyping and closures to simulate a Greeter class in JavaScript. The body of the code is wrapped with a self-invoking function to take the variables and functions out of the global JavaScript scope. This is important feature that helps avoid naming collisions between variables and functions. In cases where you’d like to wrap a class in a naming container (similar to a namespace in C# or a package in Java) you can use TypeScript’s module keyword. The following code shows an example of wrapping an AcmeCorp module around the Greeter class. In order to create a new instance of Greeter the module name must now be used. This can help avoid naming collisions that may occur with the Greeter class.   module AcmeCorp { export class Greeter { greeting: string; constructor (message: string) { this.greeting = message; } greet() { return "Hello, " + this.greeting; } } } var greeter = new AcmeCorp.Greeter("world"); In addition to being able to define custom classes and modules in TypeScript, you can also take advantage of inheritance by using TypeScript’s extends keyword. The following code shows an example of using inheritance to define two report objects:   class Report { name: string; constructor (name: string) { this.name = name; } print() { alert("Report: " + this.name); } } class FinanceReport extends Report { constructor (name: string) { super(name); } print() { alert("Finance Report: " + this.name); } getLineItems() { alert("5 line items"); } } var report = new FinanceReport("Month's Sales"); report.print(); report.getLineItems();   In this example a base Report class is defined that has a variable (name), a constructor that accepts a name parameter of type string, and a function named print(). The FinanceReport class inherits from Report by using TypeScript’s extends keyword. As a result, it automatically has access to the print() function in the base class. In this example the FinanceReport overrides the base class’s print() method and adds its own. The FinanceReport class also forwards the name value it receives in the constructor to the base class using the super() call. TypeScript also supports the creation of custom interfaces when you need to provide consistency across a set of objects. The following code shows an example of an interface named Thing (from the TypeScript samples) and a class named Plane that implements the interface to drive consistency across the app. Notice that the Plane class includes intersect and normal as a result of implementing the interface.   interface Thing { intersect: (ray: Ray) => Intersection; normal: (pos: Vector) => Vector; surface: Surface; } class Plane implements Thing { normal: (pos: Vector) =>Vector; intersect: (ray: Ray) =>Intersection; constructor (norm: Vector, offset: number, public surface: Surface) { this.normal = function (pos: Vector) { return norm; } this.intersect = function (ray: Ray): Intersection { var denom = Vector.dot(norm, ray.dir); if (denom > 0) { return null; } else { var dist = (Vector.dot(norm, ray.start) + offset) / (-denom); return { thing: this, ray: ray, dist: dist }; } } } }   At first glance it doesn’t appear that the surface member is implemented in Plane but it’s actually included automatically due to the public surface: Surface parameter in the constructor. Adding public varName: Type to a constructor automatically adds a typed variable into the class without having to explicitly write the code as with normal and intersect. TypeScript has additional language features but defining static types and creating classes, modules, and interfaces are some of the key features it offers. So is TypeScript right for you and your applications? That’s a not a question that I or anyone else can answer for you. You’ll need to give it a spin to see what you think. In future posts I’ll discuss additional details about TypeScript and how it can be used with enterprise-scale JavaScript applications. In the meantime, I’m in the process of working with John Papa on a new Typescript course for Pluralsight that we hope to have out in December of 2012.

  Read the article

• Good resources and tools for modern, heavy JavaScript development?

  - by Matt Greer

  I am interested in doing some projects that involve heavy use of JavaScript. Namely HTML5 based canvas games, potentially using node.js as well. I am interested in learning modern best practices, tools and resources for JavaScript. JavaScript is tough to research because you end up wading through a lot of really outdated material, hailing from the times that "JavaScript" was a four letter word. If you are heavily involved in JavaScript programming... What text editor or IDE do you use? What unit testing framework do you use? Do you use Selenium, or something else? What other tools do you use? What communities exist that discuss recent advents in JavaScript? What books do you read/refer to? What blogs do you read?

  Read the article

• Preserve onchange for a dropdown list when setting the value with Javascript.

  - by Zac Altman

  I have a dropdown list with a piece of code that is run when the value is changed: <select name="SList" onchange="javascript:setTimeout('__doPostBack(\'SList\',\'\')', 0)" id="SList"> Everything works fine when manually done. As an option is selected, the onchange code is called. The problem begins when I try to change the selected value using a piece of Javscript. I want to be able to automatically change the selected option using JS, whilst still having the onchange code called, exactly as if done manually. I try calling this: form.SList.value = "33"; The right option is selected, but the onchange code does not get called. So then I try doing this: form.SList.value = "33"; javascript:setTimeout('__doPostBack(\'SList\',\'\')', 0); The right value is not selected and nothing happens. FYI, the code is done in ASP.NET and Javascript. What can I run to change the selected option whilst still calling the onchange code?

  Read the article

• Hijax == sneaky Javascript redirects? Will I get banned from Google?

  - by Chris Jacob

  Question Will I get penalised as "sneaky Javascript redirects" by Google if I have the following Hijax setup (which requires a JavaScript redirect on the page indexed by google). Goal I want to implement Hijax to enable AJAX content to be accessibile to non-JavaScript users and search engine crawlers. Background I'm working on a static file server (GitHub Pages). No server side tricks allowed (so Google's #! "hash bang" solution is not an option). I'm trying to keep my files DRY. I don't want to repeat the common OUTER template in all my files i.e. header, navigation menu, footer, etc They will live in the main index.html Setup the Hijax index.html page contains all OUTER html/css/js... the site's template. index.html has a <div id="content"> which defaults to containing the "homepage" html. index.html has a navigation menu, with a Hijax link to an "about" page. With JavaScript disabled (e.g. crawler) it follows link to /about.html. With JavaScript enabled (e.g. most people) the link updates the url hash fragment to /#about and jQuery replaces the <div id="content"> innerHTML with $("#content").load("about.html #inner-container");. AJAX content about.html does not contain anything extra to try an cloak content for crawlers. about.html file contains enough HTML / CSS / JavaScript to display /about.html as a standalone page with it's own META data... e.g. <html><head><title>About</title>...</head><body></body></html>. about.html has NO OUTER HTML template (i.e. header, navigation menu, footer, etc). about.html <body> contains a <div id="inner-container"> which holds the content that is injected into index.html. about.html has a <noscript> tag as the first child of <body> which explains to non-JavaScript users that they are viewing the about page "inner content" - with a link to navigate to the index.html page to get the full page layout with menu. The (Sneaky?) Redirect Google indexes the /about.html page. However when a person with JavaScript enabled visits that page there is no OUTER html template (e.g. header, navigation menu, footer, etc). So I need to do a JavaScript redirect to get the person over the /#about page (deeplinking to the "about" page "state" in index.html). I'm thinking of doing a "redirect on click or after 10 seconds". The end results is that user ends up on an "enhanced" page back on index.html with all it's OUTER template - but the core "page" content is practically identical. Known issue with inbound links e.g. Share / Bookmarking It seems that if a user shares the URL /#about on their blog, when allocating inbound links to my site Google ignores everything after the # ... it allocates value to the / page - See: http://stackoverflow.com/questions/5028405/hashbang-vs-hijax/5166665#5166665. I can only try an minimise this issue offering "share" buttons on the page with the appropriate urls i.e. /about.html. Duplicate Sorry. I posted this same question over on http://stackoverflow.com/questions/5561686/hijax-sneaky-javascript-redirects-will-i-get-banned-from-google ... then realised it probably belongs more on this Stack Exchange site... Not sure if I should delete the Stack Overflow question? Or just leave it on both sites? Please leave comment.

  Read the article

• What are the typical reasons Javascript developed on Firefox fails on IE?

  - by karlthorwald

  I developed some javascript enhanced pages that run fine on recent Firefox and Safari. I missed to check in Internet Explorer, and now I find the pages don't work on IE 6 and 7 (so far). The scripts are somehow not executed, the pages show as if javascript wasn't there, although some javascript is executed. I am using own libraries with dom manipulation, from YUI 2 I use YUI-Loader and the XML-Http-Request, and on one page I use "psupload", which depends on JQuery. I am installing Microsoft Script Editor from Office XP and will now debug. I will also write specific tests now. What are the typical failing points of IE? What direction I can keep my eyes open. I found this page, which shows some differences: http://www.quirksmode.org/compatibility.html Can you from your experience name some typical things I should look for first? I will also ask more questions here for specific tasks later, but for now I am interested in your experience why IE usually fails on scripts that run fine in Firefox

  Read the article

• Function currying in Javascript

  - by kerry

  Do you catch yourself doing something like this often? 1: Ajax.request('/my/url', {'myParam': paramVal}, function() { myCallback(paramVal); }); Creating a function which calls another function asynchronously is a bad idea because the value of paramVal may change before it is called.  Enter the curry function: 1: Function.prototype.curry = function(scope) { 2: var args = []; 3: for (var i=1, len = arguments.length; i < len; ++i) { 4: args.push(arguments[i]); 5: } 6: var m = this; 7: return function() { 8: m.apply(scope, args); 9: }; 10: } This function creates a wrapper around the function and ‘locks in’ the method parameters.  The first parameter is the scope of the function call (usually this or window).  Any remaining parameters will be passed to the method call.  Using the curry method the above call changes to: 1: Ajax.request('/my/url', {'myParam': paramVal}, myCallback.curry(window,paramVal)); Remember when passing objects to the curry method that the objects members may still change.

  Read the article

• Pass Extra Parameters to JavaScript Callback Function

  - by BRADINO

  Here is a simple example of a function that takes a callback function as a parameter. query.send(handleQueryResponse); function handleQueryResponse(response){      alert('Processing...'); } If you wanted to pass extra variables to the callback function, you can do it like this. var param1 = 'something'; var param2 ='something else'; query.send(function(response) { handleQueryResponse(response, param1, param2) }); function handleQueryResponse(response,param1,param2){      alert('Processing...');      alert(param1);      alert(param2); }

  Read the article

• javascript game loop and game update design

  - by zuo

  There is a main game loop in my program, which calls game update every frame. However, to make better animation and better control, there is a need to implement a function like updateEveryNFrames(n, func). I am considering implementing a counter for each update. The counter will be added by one each frame. The update function will be invoked according to the counter % n. For example, in a sequence of sprites animation, I can use the above function to control the speed of the animation. Can some give some advice or other solutions?

  Read the article

• Experience formula with javascript

  - by StealingMana

  I'm having trouble working out a formula using this experience curve to get the total exp after each level. I bet its easy and im just over thinking it. maxlvl = 10; increment = 28; baseexp = 100; function calc(){ for (i = 0;i<(maxlvl*increment);i+=increment){ expperlvl = baseexp + i; document.writeln(expperlvl); } } I figured it out. maxlvl=6; base=200; increment=56; function total(){ totalxp= (base*(maxlvl-1))+(increment*(maxlvl-2)*(maxlvl-1)/2); document.write(totalxp); }

  Read the article

• What is wrong with my Dot Product? [Javascript]

  - by Clay Ellis Murray

  I am trying to make a pong game but I wanted to use dot products to do the collisions with the paddles, however whenever I make a dot product objects it never changes much from .9 this is my code to make vectors vector = { make:function(object){ return [object.x + object.width/2,object.y + object.height/2] }, normalize:function(v){ var length = Math.sqrt(v[0] * v[0] + v[1] * v[1]) v[0] = v[0]/length v[1] = v[1]/length return v }, dot:function(v1,v2){ return v1[0] * v2[0] + v1[1] * v2[1] } } and this is where I am calculating the dot in my code vector1 = vector.normalize(vector.make(ball)) vector2 = vector.normalize(vector.make(object)) dot = vector.dot(vector1,vector2) Here is a JsFiddle of my code currently the paddles don't move. Any help would be greatly appreciated

  Read the article

• Javascript and PHP how should I en/decode my data

  - by Ron

  Hello everyone. I whould like to know in what encryption should I encode my data and why first of all, I use GET method because it is search engine inside website. second, I use RTL language (hebrew) and thrid which basically is why I ask this question - firefox and safari (as I understood) encode and decode urls automaticly so if I encoded url, in firefox I will see it decoded which is good but if I copy-paste the url to the address bar and than enter the site firefox encode the uncoded url to utf (i think). anyway, what en/decode should I use, and how can I overcome the firefox auto en/decode?

  Read the article

• javascript complex recurrsion [on hold]

  - by Achilles

  Given Below is my data in data array. What i am doing in code below is that from that given data i have to construct json in a special format which i also gave below. //code start here var hierarchy={}; hierarchy.name="Hierarchy"; hierarchy.children=[{"name":"","children":[{"name":"","children":[]}]}]; var countryindex; var flagExist=false; var data = [ {country :"America", city:"Kansas", employe:'Jacob'}, {country :"Pakistan", city:"Lahore", employe:'tahir'}, {country :"Pakistan", city:"Islamabad", employe:'fakhar'} , {country :"Pakistan", city:"Lahore", employe:'bilal'}, {country :"India", city:"d", employe:'ali'} , {country :"Pakistan", city:"Karachi", employe:'eden'}, {country :"America", city:"Kansas", employe:'Jeen'} , {country :"India", city:"Banglore", employe:'PP'} , {country :"India", city:"Banglore", employe:'JJ'} , ]; for(var i=0;i<data.length;i++) { for(var j=0;j<hierarchy.children.length;j++) { //for checking country match if(hierarchy.children[j].name==data[i].country) { countryindex=j; flagExist=true; break; } } if(flagExist)//country match now no need to add new country just add city in it { var cityindex; var cityflag=false; //hierarchy.children[countryindex].children.push({"name":data[i].city,"children":[]}) //if(hierarchy.children[index].children!=undefined) for(var k=0;k< hierarchy.children[countryindex].children.length;k++) { //for checking city match if(hierarchy.children[countryindex].children[k].name==data[i].city) { // hierarchy.children[countryindex].children[k].children.push({"name":data[i].employe}) cityflag=true; cityindex=k; break; } } if(cityflag)//city match now add just empolye at that city index { hierarchy.children[countryindex].children[cityindex].children.push({"name":data[i].employe}); cityflag=false; } else//no city match so add new with employe also as this is new city so its emplye will be 1st { hierarchy.children[countryindex].children.push({"name":data[i].city,children:[{"name":data[i].employe}]}); //same as above //hierarchy.children[countryindex].children[length-1].children.push({"name":data[i].employe}); } flagExist=false; } else{ //no country match adding new country //with city also as this is new city of new country console.log("sparta"); hierarchy.children.push({"name":data[i].country,"children":[{"name":data[i].city,"children":[{"name":data[i].employe}]}]}); // hierarchy.children.children.push({"name":data[i].city,"children":[]}); } //console.log(hierarchy); } hierarchy.children.shift(); var j=JSON.stringify(hierarchy); //code ends here //here is the json which i seccessfully formed from the code { "name":"Hierarchy", "children":[ { "name":"America", "children":[ { "name":"Kansas", "children":[{"name":"Jacob"},{"name":"Jeen"}]}]}, { "name":"Pakistan", "children":[ { "name":"Lahore", "children": [ {"name":"tahir"},{"name":"bilal"}]}, { "name":"Islamabad", "children":[{"name":"fakhar"}]}, { "name":"Karachi", "children":[{"name":"eden"}]}]}, { "name":"India", "children": [ { "name":"d", "children": [ {"name":"ali"}]}, { "name":"Banglore", "children":[{"name":"PP"},{"name":"JJ"}]}]}]} Now the orignal problem is that currently i am solving this problem for data of array of three keys and i have to go for 3 nested loops now i want to optimize this solution so that if data array of object has more than 3 key say 5 {country :"America", state:"NewYork",city:"newYOrk",street:"elm", employe:'Jacob'}, or more than my solution will not work and i cannot decide before how many keys will come so i thought recursion may suit best here. But i am horrible in writing recurrsion and the case is also complex. Can some awesome programmer help me writing recurrsion or suggest some other solution.

  Read the article

• Rotate sphere in Javascript / three.js while moving on x/z axes

  - by kaipr

  I have a sphere/ball in three.js which I want to "roll" arround on a x/z axis. For the z axe I could simply do this no matter what the current x and y rotation is: sphere.roll_z = function(distance) { sphere.position.z += distance; sphere.rotation.x += distance > 0 ? 0.05 : -0.05; } But how can I roll it along the x axe? And how could I properly do the roll_z? I've found a lot about quateration and matrixes, but I can't figure out how to use them properly to achieve my (rather simple) goal. I'm aware that I have to update multiple rotations and that I have to calculate how far to rotate the sphere to match the distance, but the "how" is the question. It's probably just lack of mathematical skills which I should train, but a working example/short explanation would help alot to start with.

  Read the article

• Drawing isometric map in canvas / javascript

  - by Dave

  I have a problem with my map design for my tiles. I set player position which is meant to be the middle tile that the canvas is looking at. How ever the calculation to put them in x:y pixel location is completely messed up for me and i don't know how to fix it. This is what i tried: var offset_x = 0; //used for scrolling on x var offset_y = 0; //used for scrolling on y var prev_mousex = 0; //for movePos function var prev_mousey = 0; //for movePos function function movePos(e){ if (prev_mousex === 0 && prev_mousey === 0) { prev_mousex = e.pageX; prev_mousey = e.pageY; } offset_x = offset_x + (e.pageX - prev_mousex); offset_y = offset_y + (e.pageY - prev_mousey); prev_mousex = e.pageX; prev_mousey = e.pageY; run = true; } player_posx = 5; player_posy = 55; ct = 19; for (i = (player_posx-ct); i < (player_posx+ct); i++){ //horizontal for (j=(player_posy-ct); j < (player_posy+ct); j++){ // vertical //img[0] is 64by64 but the graphic is 64by32 the rest is alpha space var x = (i-j)*(img[0].height/2) + (canvas.width/2)-(img[0].width/2); var y = (i+j)*(img[0].height/4); var abposx = x - offset_x; var abposy = y - offset_y; ctx.drawImage(img[0],abposx,abposy); } } Now based on these numbers the first render-able tile is I = 0 & J = 36. As numbers in the negative are not in the array. But for I=0 and J= 36 the position it calculates is : -1120 : 592 Does any one know how to center it to canvas view properly?

  Read the article

• Why are Javascript for/in loops so verbose?

  - by Matthew Scharley

  I'm trying to understand the reasoning behind why the language designers would make the for (.. in ..) loops so verbose. For example: for (var x in Drupal.settings.module.stuff) { alert("Index: " + x + "\nValue: " + Drupal.settings.module.stuff[x]); } It makes trying to loop over anything semi-complex like the above a real pain as you either have to alias the value locally inside the loop yourself, or deal with long access calls. This is especially painful if you have two to three nested loops. I'm assuming there is a reason why they would do things this way, but I'm struggling with the reasoning.

  Read the article

• Javascript A* path finding ENEMY MOVEMENT in 3D environment

  - by faiz

  iam trying to implement pathfinding algorithm using PATHFINDING.JS in 3D world using webgl. iam have made a matrix of 200x200. and placed my enemy(swat) in it .iam confused in implmenting the path. i have tried implementing the path by compparing the value of each array value with swat's position . it works ! but ** THE ENEMY KEEPS GOING FROM THE UNWALKABLE AREA OF MY MATRIX....like the enemy should not move from 119,100(x=119,z=100) but its moving from that co-ordinate too ..... can any one help me out in this regard .. *prob facing :* enemy (swat character keeps moving from the wall /unwalkable area) wanted solution : enemy does not move from the unwalkable path.. ** function draw() { grid = new PF.Grid(200, 200); grid.setWalkableAt( 119,100, false); grid.setWalkableAt( 107,100, false); grid.setWalkableAt( 103,104, false); grid.setWalkableAt( 103,100, false); grid.setWalkableAt( 135,100, false); grid.setWalkableAt( 103,120, false); grid.setWalkableAt( 103,112, false); grid.setWalkableAt( 127,100, false); grid.setWalkableAt( 123,100, false); grid.setWalkableAt( 139,100, false); grid.setWalkableAt( 103,124, false); grid.setWalkableAt( 103,128, false); grid.setWalkableAt( 115,100, false); grid.setWalkableAt( 131,100, false); grid.setWalkableAt( 103,116, false); grid.setWalkableAt( 103,108, false); grid.setWalkableAt( 111,100, false); grid.setWalkableAt( 103,132, false); finder = new PF.AStarFinder(); f1=Math.abs(first_person_controller.position.x); f2=Math.abs(first_person_controller.position.z); ff1=Math.round(f1); ff2=Math.round(f2); s1=Math.abs(swat.position.x); s2=Math.abs(swat.position.z); ss1=Math.round(s1); ss2=Math.round(s1); path = finder.findPath(ss1,ss2,ff1,ff2, grid); size=path.length-1; Ai(); } function Ai(){ if (i<size) { if (swat.position.x >= path[i][0]) { swat.position.x -= 0.3; if(Math.floor(swat.position.x) == path[i][0]) { i=i+1; } } else if(swat.position.x <= path[i][0]) { swat.position.x += 0.3; if(Math.floor(swat.position.x) == path[i][0]) { i=i+1; } } } if (j<size) { if((Math.abs(swat.position.z)) >= path[j][1]) { swat.position.z -= 0.3; if(Math.floor(Math.abs(swat.position.z)) == path[j][1]) { j=j+1; } } else if((Math.abs(swat.position.z)) <= path[j][1]) { swat.position.z += 0.3; if(Math.floor(Math.abs(swat.position.z)) == path[j][1]) { j=j+1; } } } }

  Read the article

• Parallel downloading of JavaScript files on page load

  - by user359650

  Below is a quote from one of the Yahoo performance pages: While a script is downloading, however, the browser won't start any other downloads, even on different hostnames. When I look at page load of our website, I can see that many scripts are being downloaded at the same time: Am I mistaken, or should the quote should instead read like this? While scripts are downloading (there can be several scripts downloading at the same time), the browser won't start any other downloads, even on different hostnames.

  Read the article

• Which JavaScript carousel zooms blocks from the playlist?

  - by Iain Hallam

  I saw a carousel/slider for displaying featured content a while ago that does something that most don't. It started fairly simply, with the top feature large, and a playlist to the side of other featured stories: Feature 1 then began to slide towards the bottom right, while feature 2 moved to occupy the main slot, and the previews of features 3 and 4 moved up: The slider had now completed a whole swap, and was ready to do the same thing with feature 3. My Google-fu seems to be lacking in finding this again; does anyone know of this slider? I think it was based on one of the frameworks, but I'm not sure whether it was jQuery or one of the others.

  Read the article

• collision detection problems - Javascript/canvas game

  - by Tom Burman

  Ok here is a more detailed version of my question. What i want to do: i simply want the have a 2d array to represent my game map. i want a player sprite and i want that sprite to be able to move around my map freely using the keyboard and also have collisions with certain tiles of my map array. i want to use very large maps so i need a viewport. What i have: I have a loop to load the tile images into an array: /Loop to load tile images into an array var mapTiles = []; for (x = 0; x <= 256; x++) { var imageObj = new Image(); // new instance for each image imageObj.src = "images/prototype/"+x+".jpg"; mapTiles.push(imageObj); } I have a 2d array for my game map: //Array to hold map data var board = [ [1,2,3,4,3,4,3,4,5,6,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1], [17,18,19,20,19,20,19,20,21,22,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1], [33,34,35,36,35,36,35,36,37,38,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1], [49,50,51,52,51,52,51,52,53,54,1,1,1,1,1,1,1,1,1,1,1,1,1,197,198,199,1,1,1,1], [65,66,67,68,146,147,67,68,69,70,1,1,1,1,1,1,1,1,216,217,1,1,1,213,214,215,1,1,1,1], [81,82,83,161,162,163,164,84,85,86,1,1,1,1,1,1,1,1,232,233,1,1,1,229,230,231,1,1,1,1], [97,98,99,177,178,179,180,100,101,102,1,1,1,1,59,1,1,1,248,249,1,1,1,245,246,247,1,1,1,1], [1,1,238,1,1,1,1,239,240,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1], [216,217,254,1,1,1,1,255,256,1,204,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1], [232,233,1,1,1,117,118,1,1,1,220,1,1,119,120,1,1,1,1,1,1,1,1,1,1,1,119,120,1,1], [248,249,1,1,1,133,134,1,1,1,1,1,1,135,136,1,1,1,1,1,1,59,1,1,1,1,135,136,1,1], [1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1], [1,1,216,217,1,1,1,1,1,1,60,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1], [1,1,232,233,1,1,1,1,1,1,1,1,1,1,1,1,1,1,204,1,1,1,1,1,1,1,1,1,1,1], [1,1,248,249,1,1,1,1,1,1,1,1,1,1,1,1,1,1,220,1,1,1,1,1,1,216,217,1,1,1], [1,1,1,1,1,1,1,1,1,1,1,1,149,150,151,1,1,1,1,1,1,1,1,1,1,232,233,1,1,1], [12,12,12,12,12,12,12,13,1,1,1,1,165,166,167,1,1,1,1,1,1,119,120,1,1,248,249,1,1,1], [28,28,28,28,28,28,28,29,1,1,1,1,181,182,183,1,1,1,1,1,1,135,136,1,1,1,1,1,1,1], [44,44,44,44,44,15,28,29,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1], [1,1,1,1,1,27,28,29,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1], [1,1,1,1,1,27,28,29,1,1,1,1,1,1,1,1,1,59,1,1,197,198,199,1,1,1,1,119,120,1], [1,1,1,1,1,27,28,29,1,1,216,217,1,1,1,1,1,1,1,1,213,214,215,1,1,1,1,135,136,1], [1,1,1,1,1,27,28,29,1,1,232,233,1,1,1,1,1,1,1,1,229,230,231,1,1,1,1,1,1,1], [1,1,1,1,1,27,28,29,1,1,248,249,1,1,1,1,1,1,1,1,245,246,247,1,1,1,1,1,1,1], [1,1,1,197,198,199,28,29,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1], [1,1,1,213,214,215,28,29,1,1,1,1,1,60,1,1,1,1,204,1,1,1,1,1,1,1,1,1,1,1], [1,1,1,229,230,231,28,29,1,1,1,1,1,1,1,1,1,1,220,1,1,1,1,119,120,1,1,1,1,1], [1,1,1,245,246,247,28,29,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,135,136,1,1,60,1,1], [1,1,1,1,1,27,28,29,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1], [1,1,1,1,1,27,28,29,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1] ]; I have my loop to place the correct tile sin the correct positions: //Loop to place tiles onto screen in correct position for (x = 0; x <= viewWidth; x++){ for (y = 0; y <= viewHeight; y++){ var width = 32; var height = 32; context.drawImage(mapTiles[board[y+viewY][x+viewX]],x*width, y*height); } } I Have my player object : //Place player object context.drawImage(playerImg, (playerX-viewX)*32,(playerY-viewY)*32, 32, 32); I have my viewport setup: //Set viewport pos viewX = playerX - Math.floor(0.5 * viewWidth); if (viewX < 0) viewX = 0; if (viewX+viewWidth > worldWidth) viewX = worldWidth - viewWidth; viewY = playerY - Math.floor(0.5 * viewHeight); if (viewY < 0) viewY = 0; if (viewY+viewHeight > worldHeight) viewY = worldHeight - viewHeight; I have my player movement: canvas.addEventListener('keydown', function(e) { console.log(e); var key = null; switch (e.which) { case 37: // Left if (playerY > 0) playerY--; break; case 38: // Up if (playerX > 0) playerX--; break; case 39: // Right if (playerY < worldWidth) playerY++; break; case 40: // Down if (playerX < worldHeight) playerX++; break; } My Problem: I have my map loading an it looks fine, but my player position thinks it's on a different tile to what it actually is. So for instance, i know that if my player moves left 1 tile, the value of that tile should be 2, but if i print out the value it should be moving to (2), it comes up with a different value. How ive tried to solve the problem: I have tried swap X and Y values for the initialization of my player, for when my map prints. If i swap the x and y values in this part of my code: context.drawImage(mapTiles[board[y+viewY][x+viewX]],x*width, y*height); The map doesnt get draw correctly at all and tiles are placed all in random positions or orientations IF i sway the x and y values for my player in this line : context.drawImage(playerImg, (playerX-viewX)*32,(playerY-viewY)*32, 32, 32); The players movements are inversed, so up and down keys move my player left and right viceversa. My question: Where am i going wrong in my code, and how do i solve it so i have my map looking like it should and my player moving as it should as well as my player returning the correct tileID it is standing on or moving too. Thanks Again ALSO Here is a link to my whole code: prototype

  Read the article

• Javascript A* path finding

  - by Veyha

  I am trying to learn A* path finding. I am using this library - https://github.com/qiao/PathFinding.js But there is one thing I don't understand how to do. To find a path from player.x/player.y (player.x and player.y are both 0) to 10/10 I use this code var path = finder.findPath(player.x, player.y, 10, 10, grid); This gives an array of where I need to move, but how do I apply this array to my player.x and player.y? The path structure looks like this path = [[0, 0], [1, 0], [1, 1], ..., [10, 10]]

  Read the article

• What determines which Javascript functions are blocking vs non-blocking?

  - by Sean

  I have been doing web-based Javascript (vanilla JS, jQuery, Backbone, etc.) for a few years now, and recently I've been doing some work with Node.js. It took me a while to get the hang of "non-blocking" programming, but I've now gotten used to using callbacks for IO operations and whatnot. I understand that Javascript is single-threaded by nature. I understand the concept of the Node "event queue". What I DON'T understand is what determines whether an individual javascript operation is "blocking" vs. "non-blocking". How do I know which operations I can depend on to produce an output synchronously for me to use in later code, and which ones I'll need to pass callbacks to so I can process the output after the initial operation has completed? Is there a list of Javascript functions somewhere that are asynchronous/non-blocking, and a list of ones that are synchronous/blocking? What is preventing my Javascript app from being one giant race condition? I know that operations that take a long time, like IO operations in Node and AJAX operations on the web, require them to be asynchronous and therefore use callbacks - but who is determining what qualifies as "a long time"? Is there some sort of trigger within these operations that removes them from the normal "event queue"? If not, what makes them different from simple operations like assigning values to variables or looping through arrays, which it seems we can depend on to finish in a synchronous manner? Perhaps I'm not even thinking of this correctly - hoping someone can set me straight. Thanks!

  Read the article

• Javascript: Avoid this and new - further reading? [closed]

  - by Thomas Deutsch

  I do not want this to end in a sort of religious discussion, i want to collect some sources for further reading on this topic. As shown here: Node.js Style and Structure Point 1: Avoid this and new you can find a good example when it could be better to use closures instead of a prototype, and to make every argument explicit. Ok, i agree - could be nice, but i need to know more. Can anyone recommend a good link? Would this make my code 100% object-pattern-free ? (no factory-, repository-, module- pattern?)

  Read the article

• Javascript Open a Window Full Size (Mazimized)

  - by SAMIR BHOGAYTA

  function f_open_window_max( aURL, aWinName ) { var wOpen; var sOptions; sOptions = 'status=yes,menubar=yes,scrollbars=yes,resizable=yes,toolbar=yes'; sOptions = sOptions + ',width=' + (screen.availWidth - 10).toString(); sOptions = sOptions + ',height=' + (screen.availHeight - 122).toString(); sOptions = sOptions + ',screenX=0,screenY=0,left=0,top=0'; wOpen = window.open( '', aWinName, sOptions ); wOpen.location = aURL; wOpen.focus(); wOpen.moveTo( 0, 0 ); wOpen.resizeTo( screen.availWidth, screen.availHeight ); return wOpen; }

  Read the article

< Previous Page | 13 14 15 16 17 18 19 20 21 22 23 24  | Next Page >