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• Unrecognized configuration section httpHandlers in Web.Config with Microsoft Visual Web Developer 20

  - by FatboyFudge

  Hi all, I am in need of some help with an error message I get with Microsoft Visual Web Developer 2010 Express. I would like to create a gallery for my site so I downloaded the NotesForGallery from codeplex. I have added the reference into the project like it told me to in the installation instructions. The instructions then say Register the ThumbnailHandler in the Web.Config file (httpHandlers section): <httpHandlers> … <add verb="*" path="ThumbnailHandler.ashx" type="NotesFor.ThumbnailHandler, NotesForGallery"/> … </httpHandlers> So I open the web.config file in my solution and I add it in. When I try and start the website (clicking the play button in Web Developer) I get the error message: Unrecognized configuration section httpHandlers. The complete list of errors I get are: Message 1 Could not find schema information for the element 'httpHandlers'. C:\Documents and Settings\adam\My Documents\Visual Studio 2010\WebSites\FatBoyFudge\Web.config 38 4 C:...\FatBoyFudge\ Message 2 Could not find schema information for the element 'add'. C:\Documents and Settings\adam\My Documents\Visual Studio 2010\WebSites\FatBoyFudge\Web.config 39 8 C:...\FatBoyFudge\ Message 3 Could not find schema information for the attribute 'verb'. C:\Documents and Settings\adam\My Documents\Visual Studio 2010\WebSites\FatBoyFudge\Web.config 39 12 C:...\FatBoyFudge\ Message 4 Could not find schema information for the attribute 'path'. C:\Documents and Settings\adam\My Documents\Visual Studio 2010\WebSites\FatBoyFudge\Web.config 39 21 C:...\FatBoyFudge\ Message 5 Could not find schema information for the attribute 'type'. C:\Documents and Settings\adam\My Documents\Visual Studio 2010\WebSites\FatBoyFudge\Web.config 39 50 C:...\FatBoyFudge\ Error 6 Unrecognized configuration section httpHandlers. C:\Documents and Settings\adam\My Documents\Visual Studio 2010\WebSites\FatBoyFudge\Web.config 38 Warning 7 C:\Documents and Settings\adam\My Documents\Visual Studio 2010\WebSites\FatBoyFudge\Gallery.aspx: ASP.NET runtime error: Unrecognized configuration section httpHandlers. (C:\Documents and Settings\adam\My Documents\Visual Studio 2010\WebSites\FatBoyFudge\web.config line 38) C:\Documents and Settings\adam\My Documents\Visual Studio 2010\WebSites\FatBoyFudge\Gallery.aspx 1 1 C:...\FatBoyFudge\ The project I created was a website if that helps any. The complete web.config is as follows: <configuration> <connectionStrings> <add name="ApplicationServices" connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\aspnetdb.mdf;User Instance=true" providerName="System.Data.SqlClient"/> </connectionStrings> <system.web> <compilation debug="true" targetFramework="4.0"/> <authentication mode="Forms"> <forms loginUrl="~/Account/Login.aspx" timeout="2880"/> </authentication> <membership> <providers> <clear/> <add name="AspNetSqlMembershipProvider" type="System.Web.Security.SqlMembershipProvider" connectionStringName="ApplicationServices" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/"/> </providers> </membership> <profile> <providers> <clear/> <add name="AspNetSqlProfileProvider" type="System.Web.Profile.SqlProfileProvider" connectionStringName="ApplicationServices" applicationName="/"/> </providers> </profile> <roleManager enabled="false"> <providers> <clear/> <add name="AspNetSqlRoleProvider" type="System.Web.Security.SqlRoleProvider" connectionStringName="ApplicationServices" applicationName="/"/> <add name="AspNetWindowsTokenRoleProvider" type="System.Web.Security.WindowsTokenRoleProvider" applicationName="/"/> </providers> </roleManager> </system.web> <system.webServer> <modules runAllManagedModulesForAllRequests="true"/> </system.webServer> <httpHandlers> <add verb="*" path="ThumbnailHandler.ashx" type="NotesFor.ThumbnailHandler, NotesForGallery"/> </httpHandlers> </configuration> Any help you could give me would be handy because I'm not sure what I am doing wrong

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• Runge-Kutta (RK4) integration for game physics

  - by Kai

  Gaffer on Games has a great article about using RK4 integration for better game physics. The implementation is straightforward but the math behind it confuses me. I understand derivatives and integrals on a conceptual level but I haven't manipulated equations in a long time. Here's the brunt of Gaffer's implementation: void integrate(State &state, float t, float dt) { Derivative a = evaluate(state, t, 0.0f, Derivative()); Derivative b = evaluate(state, t+dt*0.5f, dt*0.5f, a); Derivative c = evaluate(state, t+dt*0.5f, dt*0.5f, b); Derivative d = evaluate(state, t+dt, dt, c); const float dxdt = 1.0f/6.0f * (a.dx + 2.0f*(b.dx + c.dx) + d.dx); const float dvdt = 1.0f/6.0f * (a.dv + 2.0f*(b.dv + c.dv) + d.dv) state.x = state.x + dxdt * dt; state.v = state.v + dvdt * dt; } Can anybody explain in simple terms how RK4 works? Specifically, why are we averaging the derivatives at 0.0f, 0.5f, 0.5f, and 1.0f? How is averaging derivatives up to the 4th order different from doing a simple euler integration with a smaller timestep? After reading the accepted answer below, and several other articles, I have a grasp on how RK4 works. To answer my own questions: Can anybody explain in simple terms how RK4 works? RK4 takes advantage of the fact that we can get a much better approximation of a function if we use its higher-order derivatives rather than just the first or second derivative. That's why the Taylor series converges much faster than Euler approximations. (take a look at the animation on the right side of that page) Specifically, why are we averaging the derivatives at 0.0f, 0.5f, 0.5f, and 1.0f? The Runge-Kutta method is an approximation of a function that samples derivatives of several points within a timestep, unlike the Taylor series which only samples derivatives of a single point. After sampling these derivatives we need to know how to weigh each sample to get the closest approximation possible. An easy way to do this is to pick constants that coincide with the Taylor series, which is how the constants of a Runge-Kutta equation are determined. This article made it clearer for me: http://web.mit.edu/10.001/Web/Course%5FNotes/Differential%5FEquations%5FNotes/node5.html. Notice how (15) is the Taylor series expansion while (17) is the Runge-Kutta derivation. How is averaging derivatives up to the 4th order different from doing a simple euler integration with a smaller timestep? Mathematically it converges much faster than doing many Euler approximations. Of course, with enough Euler approximations we can gain equal accuracy to RK4, but the computational power needed doesn't justify using Euler.

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• Xtragrid Devexpress SetRowcellValue

  - by Learner

  const int index = 1; object val = repositoryItemComboBox3.Items[index]; gridView2.SetRowCellValue(gridView2.FocusedRowHandle, object w= gridView2.GetRowCellValue(gridView2.FocusedRowHandle, "gridColumn3",val); but w does not gets updated what do I have to do more?

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• Raudus vs ExtPascal: Delphi web developement alternatives that use ExtJS

  - by user193655

  Delphi developers has several tools (several alternatives to ASP.NET) for building web applications. While No.1 framework is Intraweb, there is a lot of interest around ExtJS, that has 2 incarnations: 1) the opensource ExtPascal 2) the closedsource Raudus Now the products are different, Raudus never supports the latest ExtJS version (while ExtPascal does because as far as I read it "almost automatically updates itself to the latest ExJS version"), Raudus "seems" much RAD (much similar to Intraweb from the RAD point of view). Anyway why chose one or the other? Why Raudus (since it is free) cannot become Open Source? Or does Raudus use ExtPascal behind the scenes?

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• How do you become a freelance developer?

  - by Dwayne

  I have been a developer for 10+ years now working for various companies; I have 5+ years of .NET and ASP.NET experience. What I want to do is break away and become my own boss. Ideally I want this to lead into owning my own company. Where do I start? Has anyone done this recently? Do you have any tips?

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• Paying great programmers more than average programmers

  - by Kelly French

  It's fairly well recognized that some programmers are up to 10 times more productive than others. Joel mentions this topic on his blog. There is a whole blog devoted to the idea of the "10x productive programmer". In years since the original study, the general finding that "There are order-of-magnitude differences among programmers" has been confirmed by many other studies of professional programmers (Curtis 1981, Mills 1983, DeMarco and Lister 1985, Curtis et al. 1986, Card 1987, Boehm and Papaccio 1988, Valett and McGarry 1989, Boehm et al 2000). Fred Brooks mentions the wide range in the quality of designers in his "No Silver Bullet" article, The differences are not minor--they are rather like the differences between Salieri and Mozart. Study after study shows that the very best designers produce structures that are faster, smaller, simpler, cleaner, and produced with less effort. The differences between the great and the average approach an order of magnitude. The study that Brooks cites is: H. Sackman, W.J. Erikson, and E.E. Grant, "Exploratory Experimental Studies Comparing Online and Offline Programming Performance," Communications of the ACM, Vol. 11, No. 1 (January 1968), pp. 3-11. The way programmers are paid by employers these days makes it almost impossible to pay the great programmers a large multiple of what the entry-level salary is. When the starting salary for a just-graduated entry-level programmer, we'll call him Asok (From Dilbert), is $40K, even if the top programmer, we'll call him Linus, makes $120K that is only a multiple of 3. I'd be willing to be that Linus does much more than 3 times what Asok does, so why wouldn't we expect him to get paid more as well? Here is a quote from Stroustrup: "The companies are complaining because they are hurting. They can't produce quality products as cheaply, as reliably, and as quickly as they would like. They correctly see a shortage of good developers as a part of the problem. What they generally don't see is that inserting a good developer into a culture designed to constrain semi-skilled programmers from doing harm is pointless because the rules/culture will constrain the new developer from doing anything significantly new and better." This leads to two questions. I'm excluding self-employed programmers and contractors. If you disagree that's fine but please include your rationale. It might be that the self-employed or contract programmers are where you find the top-10 earners, but please provide a explanation/story/rationale along with any anecdotes. [EDIT] I thought up some other areas in which talent/ability affects pay. Financial traders (commodities, stock, derivatives, etc.) designers (fashion, interior decorators, architects, etc.) professionals (doctor, lawyer, accountant, etc.) sales Questions: Why aren't the top 1% of programmers paid like A-list movie stars? What would the industry be like if we did pay the "Smart and gets things done" programmers 6, 8, or 10 times what an intern makes? [Footnote: I posted this question after submitting it to the Stackoverflow podcast. It was included in episode 77 and I've written more about it as a Codewright's Tale post 'Of Rockstars and Bricklayers'] Epilogue: It's probably unfair to exclude contractors and the self-employed. One aspect of the highest earners in other fields is that they are free-agents. The competition for their skills is what drives up their earning power. This means they can not be interchangeable or otherwise treated as a plug-and-play resource. I liked the example in one answer of a major league baseball team trying to field two first-basemen. Also, something that Joel mentioned in the Stackoverflow podcast (#77). There are natural dynamics to shrink any extreme performance/pay ranges between the highs and lows. One is the peer pressure of organizations to pay within a given range, another is the likelyhood that the high performer will realize their undercompensation and seek greener pastures.

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• ExtJS GridPanel Scrollbar does not appear in IE7 but it does in Firefox, etc

  - by Snowright

  Setup I have an accordion layout containing a "properties" panel that nests two inner panels. The first inner panel holds a Ext.DataView, while the second panel is the Ext.grid.GridPanel in question. In the screenshot below, the white space containing the folder icon is the dataview, and below that is the gridpanel. Problem In Firefox, Chrome, and Opera, there is a scrollbar that appears when my gridpanel has an overflow of properties. It is only in Internet Explorer that it does not appear. I am, however, able to scroll using my mouse scroll button in all browsers, including IE. I've also tried removing our custom css file in case it was affecting it somehow, but there was no change in doing so. I'm not sure exactly what code I should show as I don't know where the exact problem is coming from but here is the code for the mainpanel and gridpanel. var mainPanel = new Ext.Panel({ id : 'main-property-panel', title : 'Properties', height : 350, autoWidth : true, tbar : [comboPropertyActions], items : [panel1] //panel1 holds the DataView }); var propertiesGrid = new Ext.grid.GridPanel({ stripeRows : true, height : mainPanel.getSize().height-iconDataView.getSize().height-mainPanel.getFrameHeight(), autoWidth : true, store : propertiesStore, cm : propertiesColumnModel }) //Add gridpanel to mainPanel mainPanel.add(propertiesGrid); mainPanel.doLayout(); Any help into the right direction would be greatly appreciated. Thank you.

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• Where do all the old programmers go?

  - by Tony Lambert

  I know some people move over to management and some die... but where do the rest go and why? One reason people change to management is that in some companies the "Programmer" career path is very short - you can get to be a senior programmer within a few years. Leaving no way to get more money but to become a manager. In other companies project managers and programmers are parallel career paths so your project manager can be your junior. Tony

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• How do you set tab view to scroll?

  - by DrogoNevets

  I have managed to set up a tabbed view for my app (woo!) and have the following xml for the UI <TabHost xmlns:android="http://schemas.android.com/apk/res/android" android:id="@android:id/tabhost" android:layout_width="fill_parent" android:layout_height="wrap_content"> <LinearLayout android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" android:padding="5dp"> <TabWidget android:id="@android:id/tabs" android:layout_width="fill_parent" android:layout_height="wrap_content" /> <FrameLayout android:id="@android:id/tabcontent" android:layout_width="fill_parent" android:layout_height="fill_parent" /> </LinearLayout> <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <Spinner android:id="@+id/areaSpinner" android:layout_width="fill_parent" android:layout_height="@dimen/one_row" /> <Spinner android:id="@+id/cragSpinner" android:layout_width="fill_parent" android:layout_height="@dimen/one_row" /> <Spinner android:id="@+id/routeSpinner" android:layout_width="fill_parent" android:layout_height="@dimen/one_row" /> <DatePicker android:id="@+id/dateClimbed" android:layout_width="fill_parent" android:layout_height="wrap_content" /> <Spinner android:id="@+id/styleSpinner" android:layout_width="fill_parent" android:layout_height="@dimen/one_row" /> <Spinner android:id="@+id/detailsSpinner" android:layout_width="fill_parent" android:layout_height="@dimen/one_row" /> <TextView android:id="@+id/climbNotes" android:layout_width="fill_parent" android:layout_height="@dimen/three_row" /> </LinearLayout> yet am seemingly unable to scroll down to see the rest of the form (cuts off at one of the spinners, why is this? and how do i fix it?

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• CSS/HTML: How to simulate IFRAME with CSS?

  - by BBnight

  I want to have a header DIV and a footer DIV always displayed on my web page, regardless of when you scroll down the page. How do I accomplish this using only CSS (without IFRAMES) For example: <div id=header>Always display on top, regardless if you have scrolled down the page</div> <div id=main_content>...</div> <div id=footer>Always display on the bottom</div>

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• Component based game engine design

  - by a_m0d

  I have been looking at game engine design (specifically focused on 2d game engines, but also applicable to 3d games), and am interested in some information on how to go about it. I have heard that many engines are moving to a component based design nowadays rather than the traditional deep-object hierarchy. Do you know of any good links with information on how these sorts of designs are often implemented? I have seen evolve your hierarchy, but I can't really find many more with detailed information (most of them just seem to say "use components rather than a hierarchy" but I have found that it takes a bit of effort to switch my thinking between the two models). Any good links or information on this would be appreciated, and even books, although links and detailed answers here would be preferred.

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• Map external directory to web.xml

  - by prometheus

  Is there an easy way to map a directory in the web.xml or other deployment descriptor (jetty.xml, etc) files? For example, if I have a directory /opt/files/ is there a way that I can access its files and sub-directories by visiting http://localhost/some-mapping/? It strikes me that there should be some simple way of doing this, but I haven't been able to find out how (via google, stackoverflow, etc). All I've found are servlets that mimic fileservers, which is not what I would like. For reference I am using jetty on an AIX box.

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• How do I create Tetris Blocks in XNA with C#?

  - by Slateboard

  I'm making a Tetris Clone in C# with XNA, and I'm unsure of how to actually implement the blocks. I don't think that making the shapes as images will work (because parts are removed when lines are formed), so I Have blocks to make up the pieces like This. Unfortunately, I don't know how to actually define the blocks to make the pieces, nor do I know how to manipulate them to make them rotate, etc. Edit: I would also need assistance in learning how to make the Tetris Grid too.

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• FB.Event.subscribe + comments.add don't work !?

  - by user366292

  I'm trying to catch event when comment is sent. What am I doing wrong? I just want to update every user comment also to facebook group wall and that's why I need to catch the event. <fb:comments numposts="10" ></fb:comments> FB.init and event catcher: <div id="fb-root"></div> <script> window.fbAsyncInit = function() { FB.init({ appId : 'sensored-app-id', status : true, // check login status cookie : true, // enable cookies to allow the server to access the session xfbml : true // parse XFBML }); /* All the events registered */ FB.Event.subscribe('comments.add', function (response) { // do something with response alert("comment added"); }); }; (function() { var e = document.createElement('script'); e.src = document.location.protocol + '//connect.facebook.net/fi_FI/all.js'; e.async = true; document.getElementById('fb-root').appendChild(e); }()); </script>

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• Developing for Mac, without a Mac.

  - by speeder

  Hello I am a "lone wolf" game developer, and games sell more on Mac (because noone make Mac games... bizarre), so I need to make Mac games. My problem is: I don't own a Mac, and I have no way to get one (unless someone donate one to me...), I don't have money even to upgrade my crappy 3 year old PC, or buy a netbook... So, how I develop for Mac without a Mac? I guess that if I installed Mac OS on my machine, it would do, or can I just use Open Darwin instead? Or Mac OS run on virtual machines?

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• C# XNA: AI Engine?

  - by Rosarch

  I'm developing a game with zombie running around in a swamp. I want AIs to have functionality like "chase this target" or "run away". A major stumbling block is pathfinding. Is there a good pathfinding/AI engine in XNA, or should I roll my own? Does anyone have any experience with this: http://www.codeplex.com/simpleAI?

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• Adding custom options in binded dropdown in asp.net

  - by MarceloRamires

  I have a bound dropdown list populated with a table of names through a select, and databinding. it shoots selectedindexchanged that (through a postback) updates a certain gridview. What happens is, since it runs from changing the index, the one that always comes selected (alexander) can only me chosen if you choose another one, then choose alexander. poor alexander. What I want is to put a blanc option at the beginning (default) and (if possible) a option as second. I can't add this option manually, since the binding wipes whatever was in the dropdown list and puts the content of the datasource.

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• asp.NET Dynamic Data Site and asp.NET MVC-2 site together

  - by loviji

  Hi, I have created firstly ASP.NET MVC 2. and write more functionality. After I create asp.NET Dynamic Data Site. now, when I click on run button in Visual Studio, mvc app. opened in browser as http://localhost:50062. and asp.NET Dynamic Data Site as http://localhost:58395/cms/. but i want to merge this app. in one. can I use asp.NET Dynamic Data Site and asp.NET MVC-2 at the same time?

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• java Filter URL pattern specific to request params

  - by Rohit Desai

  Hi All, We have a situation where we want to use filter for URL's containing some specific request parameters. e.g htt://mydomain.com/?id=78&formtype=simple_form&....... htt://mydomain.com/?id=788&formtype=special_form&....... and so on , id are fetched at run time, I want configure filter in web.xml only if formtype=special_form. How should achieve the solution . Can filter be configure with regex patterns? Really appreciate your help on this. Thanks, Rohit

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• How to fix type names conflicts in Dynamic Data

  - by SDReyes

  Hi Guys! We're working in a Dynamic Data project that will handle entities coming from two different namespaces: myModel.Abby and myModel.Ben. whose classes are: Abby myModel.Abby.Car myModel.Abby.Lollipop Ben myModel.Ben.Car myModel.Ben.Apple So myModel.Abby.Car and myModel.Ben.Car are homonym. when I try to register both ObjectContext's, an exception is thrown telling us that there are type name conflicts between the mentioned classes (although the types belong to different namespaces). How can we overcome type-name conflicts, caused by repeated type names among different namespaces?

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• The Maths for 2D Collision Detection between an OBB and a Circle

  - by Chris

  I'm creating a 2D game and want to test for collision between an OBB (Oriented Bounding Box) and a Circle. I'm unsure of the maths and code to do this. I'm creating the game in c++ and opengl.

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• error C2146: syntax error : missing ';' before identifier 'vertices'

  - by numerical25

  I would usually search for this error. But in VS C++ Express, this error comes up for just about every mistake you do. Any how I recieve this error below error C2146: syntax error : missing ';' before identifier 'vertices' everytime I add the following code at the top of my document // Create vertex buffer SimpleVertex vertices[] = { D3DXVECTOR3( 0.0f, 0.5f, 0.5f ), D3DXVECTOR3( 0.5f, -0.5f, 0.5f ), D3DXVECTOR3( -0.5f, -0.5f, 0.5f ), }; below is the code in it's entirety. Cant figure out whats wrong. thanks // include the basic windows header file #include "D3Dapp.h" class MyGame: public D3Dapp { public: bool Init3d(); }; MyGame game; // Create vertex buffer SimpleVertex vertices[] = { D3DXVECTOR3( 0.0f, 0.5f, 0.5f ), D3DXVECTOR3( 0.5f, -0.5f, 0.5f ), D3DXVECTOR3( -0.5f, -0.5f, 0.5f ), }; // the entry point for any Windows program int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { game.InitWindow(hInstance , nCmdShow); return game.Run(); } bool MyGame::Init3d() { D3Dapp::Init3d(); return true; }

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• fbjs ajax to load content

  - by fusion

  i tried one of the examples here to load the content in the div, but apart from displaying the image, it doesn't show anything. can anyone please point out where i'm going wrong? ajax1.js: function General_Refresh(url,div){ //Showing the load image (pay attention to /> of <img document.getElementById(div).setInnerXHTML('<span id="caric"><center><img src="http://website.name/images/ajax-loader.gif" /></center></span>'); var ajax = new Ajax(); ajax.responseType = Ajax.FBML; ajax.ondone = function(data) { //Hide the loading image document.getElementById('caric').setStyle('display','none'); document.getElementById(div).setInnerFBML(data); } //If there are errors re-try ajax.onerror = function() { General_Refresh(url,div); } ajax.post(url); } quote.html: <script src="http://website.name/scripts/ajax1.js" type="text/javascript"></script> <script type="text/javascript"> <!-- General_Refresh("http://website.name/quote.php","quote"); //--> </script> <div id="wrapper"> <div id="quote"><strong>this</strong></div> </div></div>

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• Which programming language is manageable by an 11 year old kid?

  - by tangens

  Possible Duplicates: What is the easiest language to start with? What are some recommended programming resources for pre-teens? My son is 11 years old and he would like to learn a programming language. Of course his primary goal is to develop some (simple) games. Do you know of a programming language that is suitable for this situation? Summary of languages recommended in the answers Snake Wrangling for Kids (answer) Scratch (answer) Small Basic (answer) (answer) Logo NXT-G for Lego Mindstorms (answer) Alice (answer) BlueJ (answer) Squeak Smalltalk (answer) (answer) (answer) Blender Game Engine (answer) PyGame (answer) (answer) (answer) Inform (answer) Phrogram (answer) Dr Scheme (answer) eToys (answer) runrev (answer) Karel Programming (answer) Hackety Hack (answer) Visual Basic (answer) (answer) Learn to Program (answer) QBasic (answer) (answer) Visual Basic Express (answer) Processing (answer) C# (answer) JavaScript (answer) (answer) Ruby (answer) ToonTalk (answer) Flash and ActionScript (answer) StarLogo (answer) Java (answer) Kodu (answer) XNA (answer) (answer) unity3D (answer) BlitzBasic (answer)(answer) Lua (answer)

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• Detecting 'stealth' web-crawlers

  - by Jacco

  What options are there to detect web-crawlers that do not want to be detected? (I know that listing detection techniques will allow the smart stealth-crawler programmer to make a better spider, but I do not think that we will ever be able to block smart stealth-crawlers anyway, only the ones that make mistakes.) I'm not talking about the nice crawlers such as googlebot and Yahoo! Slurp. I consider a bot nice if it: identifies itself as a bot in the user agent string reads robots.txt (and obeys it) I'm talking about the bad crawlers, hiding behind common user agents, using my bandwidth and never giving me anything in return. There are some trapdoors that can be constructed updated list (thanks Chris, gs): Adding a directory only listed (marked as disallow) in the robots.txt, Adding invisible links (possibly marked as rel="nofollow"?), style="display: none;" on link or parent container placed underneath another element with higher z-index detect who doesn't understand CaPiTaLiSaTioN, detect who tries to post replies but always fail the Captcha. detect GET requests to POST-only resources detect interval between requests detect order of pages requested detect who (consistently) requests https resources over http detect who does not request image file (this in combination with a list of user-agents of known image capable browsers works surprisingly nice) Some traps would be triggered by both 'good' and 'bad' bots. you could combine those with a whitelist: It trigger a trap It request robots.txt? It doest not trigger another trap because it obeyed robots.txt One other important thing here is: Please consider blind people using a screen readers: give people a way to contact you, or solve a (non-image) Captcha to continue browsing. What methods are there to automatically detect the web crawlers trying to mask themselves as normal human visitors. Update The question is not: How do I catch every crawler. The question is: How can I maximize the chance of detecting a crawler. Some spiders are really good, and actually parse and understand html, xhtml, css javascript, VB script etc... I have no illusions: I won't be able to beat them. You would however be surprised how stupid some crawlers are. With the best example of stupidity (in my opinion) being: cast all URLs to lower case before requesting them. And then there is a whole bunch of crawlers that are just 'not good enough' to avoid the various trapdoors.

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