Jquery Modal Pop Up

I am using asp.net image button when we click the image button Modal popup will display. now My problem is when i click the button popup is coming but it post back to the server after that popup window is closed can u give the solution for this

My Code is

<asp:ImageButton ID="imgemail" runat="server" ImageUrl=开发者_Python百科"~/images/images.jpg" /> 

$("#imgemail").click(function() {

 $("#dialog").dialog("open"); 

});

Unless you have a specific need, there is no point in doing an ASP.NET Image Button, you could do something like this.

<a id="lnkEmail">
    <img src="/images/images.jpg" alt="Your text" />
</a>

$("#lnkEmail").click(function() {

 $("#dialog").dialog("open"); 

});

Now, you would want to set additional attributes on the image etc, but you get the idea.