As part of an overall effort to optimize HTTP-related performance of Web.UI, version 2007.2 includes a new mechanism for reducing the overhead of client script deployment. Since the script files themselves are of manageable size, and drastically benefit from compression in many cases, the biggest overhead comes from HTTP round-trips. Each Web.UI control typically depends on anywhere from one or two to several script files, so the number of separate requests can affect the load times in a web application.

The ComponentArt ScriptHandler, a new feature of Web.UI 2007.2 can be used to dramatically increase the efficiency of this aspect of Web.UI, pushing it to its theoretical limits.
 

With ScriptHandler, you have the ability to do choose between three different ways of sending ComponentArt client scripts to the client in your web application:

1. Status quo

By default, script rendering will work exactly the same way it has until now. Each control will output its own set of scripts or register them with the ASP.NET AJAX ScriptManager. In the latter case, the scripts will get compressed by default, but the overhead of multiple HTTP requests will remain.

2. Output the entire Web.UI client library in one request

The new script deployment mechanism allows you to combine all Web.UI client script libraries into one and send them to the client as one chunk. This minimizes the number of HTTP requests (to a single one), and maximizes the benefits of compression. As of version 2007.2, the combined size of all client scripts, compressed, is 327 KB. Due to browser caching, this means that the Web.UI scripts will get loaded all at once, and only the first time a user visits the site.

To enable this feature, simply add the following two entries to your web application’s web.config file:

in <httpHandlers>:

            <add type="ComponentArt.Web.UI.ScriptHandler,ComponentArt.Web.UI" path="ComponentArtScript.axd" verb="*"/>

in <appSettings>:

<add key="ComponentArtScriptControls" value="All" />

3. Output combined scripts of select controls in one request

If the size of the one-time download in option 2 is a concern, it can be further optimized by excluding from the download those controls which are never used in your web application. For instance, if you only use Grid, TreeView and Menu in your application, you can change the appSetting to

<add key="ComponentArtScriptControls" value="Grid,TreeView,Menu" />

This will cause the Web.UI framework to combine all the scripts on which these three controls depend on into one chunk, and send it to the client compressed, and in a way which promotes indefinite client-side caching. For the above controls, the download size would be 90 KB.

Note again that this is an application-wide setting, so the list of controls should include any ComponentArt controls that are used anywhere in the application.
 

This feature is available for preview now, in the Beta 2 build of Web.UI 2007.2. We hope you find it useful, and that it helps you squeeze that extra bit of performance out of our control suite and your website.