A: 

Could it be because of id-mangling? ASP.NET feels that it can freely change your IDs for tags with runat="server". Check your generated HTML and check the ID of the form.

To solve that particular case, you can add a wrapping element that does not runat=server to the form, and target the form throught that one.

<div id="myform_wrapper">
    <!-- your form here -->
</div>

and target it with

$("#myform_wrapper form")
Magnar
A: 

i do that,but don't submit data to response.aspx however, and the form default target url is the self ,is webform1,aspx,so the data don't post. How solve the problem.