I want to intercept any postbacks in the current page BEFORE it occurs . I want to do some custom manipulation before a postback is served. Any ideas how to do that?
See Question&Answers more detail:osI want to intercept any postbacks in the current page BEFORE it occurs . I want to do some custom manipulation before a postback is served. Any ideas how to do that?
See Question&Answers more detail:osThere's a couple of things you can do to intercept a postback on the client.
The __doPostBack function looks like this:
function __doPostBack(eventTarget, eventArgument) {
if (!theForm.onsubmit || (theForm.onsubmit() != false)) {
theForm.__EVENTTARGET.value = eventTarget;
theForm.__EVENTARGUMENT.value = eventArgument;
theForm.submit();
}
}
Notice that it calls "theForm.onsubmit()" before actually doing the postback. This means that if you assign your form an onsubmit javascript function, it will always be called before every postback.
<form id="form1" runat="server" onsubmit="return myFunction()">
Alternately, you can actually override the __doPostBack function and replace it with your own. This is an old trick that was used back in ASP.Net 1.0 days.
var __original= __doPostBack;
__doPostBack = myFunction();
This replaces the __doPostBack function with your own, and you can call the original from your new one.