Back in March, I attended the spring DevConnections conference in Orlando (which was awesome).  I sat in one of Scott Guthrie's sessions named "ASP.NET 2.0, ASP.NET AJAX, and Visual Studio 2005 Tips and Tricks."  He showed a ton of cool stuff in that session, but one of the things that caught my eye was the new $get function available in ASP.NET AJAX.  It is really just an alias to the document.getElementById function in the DOM. 

However, I saw some potential in it that might solve one of the issues that constantly frustrated me when using master pages ... so I sent Scott and email to suggest some functionality that his team might consider building into future versions of the framework.  To my surprise Scott emailed me back the next day (which was a Sunday) with a really simple work-around that has really helped me out.  So I thought I would share it with the rest of the world.  Here is the guts of my original email followed by Scott's response:

It is my understanding that the $get command is simply a shorthand version of the document.getElementById() method.  One thing that has been frustrating since I switched over to the ASP.NET 2.0 way of doing things, is when you use MasterPages you have to account for how ASP.NET will rename your server-side elements when it renders them to the client.  Since I do find myself writing quite a bit of JavaScript, finding and accounting for these fully qualified names is probably more of a hassle than it should be.  Is there any way you guys could work into the .NET Framework v3.5 a way use the $get command to retrieve values without having to use their fully qualified name.  I realize one option is to render JavaScript from the server to dynamically insert the assigned ID, but that seems like quite a bit of overhead, and if it was built into the framework your team could also tune it for better performance as well.

It seems that MasterPages are so useful, but as JavaScript becomes more prevalent throughout web applications I am tempted to revert back to the “old school” approach of PageStart and PageEnd user controls to encapsulate a page instead of MasterPages.  I have put a lot of thought into this and realize it is a complicated problem to solve, but I just wanted to mention it because I think it is really important and will become more important with the rise of technologies like AJAX.

Hi Cal,

Right now $get() is indeed just a short-cut for document.getElementByID().  We are looking to improve the ID naming of elements over the next year to give you more control over how they are rendered.

In the meantime, you can use a technique where you render the client name into JavaScript using the Control.ClientID property:

   var myControl = <%= MyControl.ClientID %>;

You can then write this JavaScript code to dynamically load the control regardless of where it is used on the page:

   $get(myControl);

Hope this helps,
Scott

var txtName = $get('<%= txtName.ClientID %>');
txtName.value = "Lorem ipsum";