Your best bet is to look at the page events
You can add your custom code in these events to see if your PageID matches and prevent the page from loading.
1. Look at the page load, you can do an if test to see if the page is post back
2. Look at the unload event
If you dont understand the post back read this article for a basic explaination
Detecting Refresh or Postback in ASP.NET
Make sure the you have you are calling you function onPostBack like in the example or you wont generate the new id on refreshing the page.
<form id="form1" runat="server" onsubmit="onPostBack()">