Someone asked me to compare Silverlight / HTML development. I realized that the question can be answered in many ways: Below is the high level comparison between a HTML /JavaScript client and Silverlight client and why silverlight was chosen over HTML / JavaScript client (based on type
of users and major functionalities provided): 1. For end users
Browser compatibility Silverlight is a plug-in and requires installation first. However, it does provides consistent look and feel across all browsers. For HTML / DHTML, there is a need to tweak JavaScript for each
of the
browser supported. In fact, tags like <span> and <div> works differently on different
browser / version. So, HTML works on most
of the systems but also requires lot
of efforts coding-wise to adhere to all standards/ browsers / versions.
Out of browser support No support in HTML. Third party tools like Google gears offers some functionalities but there are lots
of issues around platform and accessibility.
Out of box support for out-of-browser support. provides features like drag and drop onto application surface. Cut and copy paste in HTML HTML is displayed in browser; which, in turn provides facilities for cut copy and paste. Silverlight (specially 4) provides rich features for cut-copy-paste along with full control over what can be cut copy pasted by end users and .advanced features like visual tree printing. Rich user experience HTML can provide some rich experience by use
of some JavaScript libraries like JQuery. However, extensive use
of JavaScript combined with various versions
of browsers and the supported JavaScript makes the solution cumbersome. Silverlight is meant for RIA experience. User data storage on client end In HTML only small amount
of data can be stored that too in cookies. In Silverlight large data may be stored, that too in secure way. This increases the response time. Post back In HTML / JavaScript the post back can be stopped by use
of AJAX. Extensive use
of AJAX can be a bottleneck as
browser stack is used for the calls. Both look and feel and data travel over network. In Silverlight everything run the client side. Calls are made to server ONLY for data; which also reduces network traffic in long run. 2. For Developers Coding effort HTML / JavaScript can take considerable amount to code if features (requirements) are rich. For AJAX like interfaces; knowledge
of third party kits like DOJO / Yahoo UI / JQuery is required which has steep learning curve. ASP .Net coding world revolves mostly along <table> tags for alignments whereas most popular tools provide <div> tags; which requires lots
of tweaking. AJAX calls can be a bottlenecks for performance, if the calls are many. In Silverlight; coding is in C#, which is managed code. XAML is also very intuitive and Blend can be used to provide look and feel. Event handling is much clean than in JavaScript. Provides for many clean patterns like MVVM and composable application. Each call to server is asynchronous in silverlight. AJAX is in built into silverlight. Threading can be done at the client side itself to provide for better responsiveness; etc. Debugging Debugging in HTML / JavaScript is difficult. As JavaScript is interpreted; there is NO compile time error handling. Debugging in Silverlight is very helpful. As it is compiled; it provides rich features for both compile time and run time error handling. Multi -targeting browsers HTML / JavaScript have different rendering behaviours in different browsers / and their versions. JavaScript have to be written to sublime the differences in
browser behaviours. Silverlight works exactly the same in all browsers and works on almost all popular
browser. Multi-targeting desktop No support in HTML / JavaScript Silverlight is very close to WPF. Bot the platform may be easily targeted while maintaining the same source code. Rich toolkit HTML /JavaScript have limited toolkit as controls Silverlight provides a rich set
of controls including graphs, audio, video, layout, etc. 3. For Architects Design Patterns Silverlight provides for patterns like MVVM (MVC) and rich (fat) client architecture. This segregates the "separation
of concern" very clearly. Client (silverlight) does what it is expected to do and server does what it is expected
of. In HTML / JavaScript world most
of the processing is done on the server side. Extensibility Silverlight provides great deal
of extensibility as custom controls may be made. Extensibility is NOT restricted by
browser but by the plug-in silverlight runs in. HTML / JavaScript works in a certain way and extensibility is generally done on the server side rather than client end. Client side is restricted by the limitations
of the
browser. Performance Silverlight provides localized storage which may be used for cached data storage. this reduces the response time. As processing can be done on client side itself; there is no need for server round trips. this decreases the round about time. Look and feel
of the application is downloaded ONLY initially, afterwards ONLY data is fetched form the server. Security Silverlight is compiled code downloaded as .XAP; As compared to HTML / JavaScript, it provides more secure sandboxed approach. Cross - scripting is inherently prohibited in silverlight by default. If proper guidelines are followed silverlight provides much robust security mechanism as against HTML / JavaScript world. For example; knowing server Address in obfuscated JavaScript is easier than a compressed compiled obfuscated silverlight .XAP file. Some
of these like (offline and Canvas support) will be available in HTML5. However, the timelines are not encouraging at all. According to Ian Hickson, editor
of the HTML5 specification, the specification to reach the W3C Candidate Recommendation stage during 2012, and W3C Recommendation in the year 2022 or later. see http://en.wikipedia.org/wiki/HTML5 for details. The above is MY opinion. I will love to hear yours; do let me know via comments. Technorati Tags: Silverlight
