This is a video version of an article I had written earlier around handling enter key with the ASP.NET Webform’s DefaultButton property. So its quite old and a feature of ASP.NET 2.0 but works fine with 3.5 version as well.
Note: In the master page scenario at the end of the video, the code this.form1.DefaultButton = Button1.UniqueID needs to come in the Page_Load event and not inside the button click event. I just typed the syntax there.
Click here for a text version of this article
Cheers!!!