Please see sample Project. (VS2008)
default.aspx - contains button which open RadWindow with page.htm.
page.html catch onunload event - just show message “unloadcurrentpage”. If I push reload or close icon on RadWindow - I see my message, but only in IE 7. On FF I don't see. As I know there is no problem with unload event without using RadWindow in FF.
Instead of the onunload event of the content page you can use the OnClientBeforeClose event of the Radwindow control. There you can attach a function ( in the project I used the add_beforeClose() function of the RadWindow control) to this event, implement your logic in it and you can interrupt canceling if you need this. I modified your project in order to achieve the desired behavior by using the client side API of the RadWindow control and I have attached the project to this thread.
I hope this helps.
the Telerik team
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