AJAX :: Cancel Updatepanel Callback With Javascript Or In Any Other Way?

I have a updatepanel which contains of a few dynamically created ImageButtons (the ImageButtons are placed in a panel inside the updatepanel) Since the imagebuttons are children of the updatepanel they automatically triggers a callback to server, fine. But I want the user to be able to cancel the callback after clicking on the imgbutton, preferably through a javascript window.confirm.

I have managed to make it work with a jquery function returning false (i dont know why it works, dont really understand asp.net ajax functionality) but it only works until a callback is done, then I guess I have to rebind the jquery to the controls in the updatepanel or?this turned out to be a jquery question. How do I rebind the recently loaded controls in my updatepanel to my jqyery function? the controls all have the same class and I use that to trigger the jquery function.

aspx file
..
..
$('.myImgButtons').click(function(){
if(window.confirm('Cancel callback?') )
return false;
});
..
..
<asp:UpdatePanel ..... >
<ContentTemplate>
<asp:panel id="myPanel" ........ ></asp:Panel>
</ContentTemplate>
<Triggers>
..whatever..
</Triggers>
</asp:UpdatePanel>
aspx.cs file
..
..
ImageButton dyn_ImgButton = new ImageButton();
dyn_ImgButton.Attributes.Add("class", "myImgButtons");
add dyn_ImgButton to myPanel
..
..