ASP.NET 2.0 & the new WebResource.axd handler

ASP.NET 2.0 provides some new Page Class methods that insert dynamic javascript into your .aspx page. This is the case for SetFocus method that is a new Page method that inherits the Control class.

You will notice that when you call the SetFocus method in a page and view the source of the rendered page a WebResource.axd handler and some javascript has attached itself.
<script src=”/Test/WebResource.axd?d=-C1iQIXP-aLieQ9wSoBAxg2&amp;t=632677431704275456″ type=”text/javascript”></script>

This method is defined in the WebForms.js file described below.
<!–
WebForm_AutoFocus(‘UserTextBox’);// –>
</script>

 

Took me a while to find a some decent content on the subject and Peter explains things very clearly.

 

By Peter A. Bromberg, Ph.D

“This method is defined in WebForms.js which is now an embedded resource inside System.Web.dll, and it is served using the new WebResource.axd handler. WebResource.axd alleviates many of the problems that are present in ASP.NET 1.1 with the asp.net script files folder where you used to have to serve the client script (.js) files that are required for things like validators. There are a number of other javascript embedded resources in System.Web. If you are curious what Microsoft have been doing, and you’d like to see them all download this text file.

In ASP.NET 2.0 there are many more scripts since they are leveraging more client side functionality, for example GridView can now do sorting and paging without doing a PostBack. This is all done with the new Script Callback mechanism.”

WebResource.axd
WebResource.axd is the new Handler that enables control and page developers to download resources that are embedded in an assembly. This is a valuable and welcome tool, since control developers may want to include a javascript file (.js) or images (.jpg, .gif) for their controls and there is now a built-in method to access these. So now you can do things like: <script src='<PUT THE STRING RETURNED BY Page.GetWebResourceUrl(typeof(YourControl), “YourScript.js”)> HERE’>
Another advantage is that you can use localized assemblies and you will have the correct image or script localized based on the deployment.”