'this.get_element() is undefined' when using UpdateProgress ASP.NET AJAX

I'm getting a JavaScript error in the ASP.NET AJAX framework when using the UpdateProgress control.

Details:

1. The UpdateProgress is inside the UpdatePanel.

2. Firebug error information:

   this.get_element() is undefined

   Sys$UI$_UpdateProgress$_startRequest()ScriptRe...373681250 (line 1931)

   anonymous()ScriptRe...373681250 (line 61)

How do I resolve this issue? Is this a known bug an开发者_高级运维d if so what are the steps I need to do to avoid it? Thanks!

---

I have had this same problem before, but I don't quite remember how I solved it. I think it is a timing issue when using the DisplayAfter property (so yes, probably a bug). Try setting DisplayAfter to 0 and see if that helps.

---

Many problems with the update panel are caused by invalid html. Can you check your page's generated html for errors in a html validator? Can you also post the whole JavaScript function or code in which the error occurred so we can determine what this is in the case?