<!DOCTYPE html>
<html>
<head>
<script runat="server">
Sub Button1_Click(sender As Object, e As EventArgs)
Response.Write("The Page containing the button is: ")
Response.Write(button1.Page)
End Sub
</script>
</head>
<body>
<form runat="server" >
<asp:Button ID="button1" OnClick="Button1_Click" Text="Get Page" runat="server" />
</form>
</body>
</html>