I think this is a javascript under IE problem, as I got it to work successfuly under Opera.
I want to have a locking mechanism for certain webpages so that only one person can have interactive access at any given time. Of course, I want them to give up the lock upon leaving the page. The best way I could think of doing this (via JSP) was to popup a window that contained the release code via the onUnload function.
Here are the relevant code snippets:
On the page in question:
Code:
<snip>
function releaseLock(){
window.open("releaseLock.jsp?lock_name=<%=request.getParameter("id")%>", "Release Locks");
}
<snip>
<body onUnload="releaseLock()"> Here's the release lock popup code:
Code:
<jsp:useBean id="user" class="dec.common.beans.UserBean" scope="session" />
<%@ page import="dec.common.locks.*" %>
<%@ page import="dec.common.authentication.*" %>
<%
String lock = request.getParameter("lock_name");
if(lock != null){
lock = lock.trim();
LockMap.getInstance().release(lock, user.getUser().getUID());
} // If lock == null, do nothing. Something broke, and the lock that was suppose
// to be released will have to expire.
%>
<html>
<head>
</head>
<body onLoad="window.close()">
<a href="javascript:void(0)"
onClick="window.close()"</a>
</body>
</html> Now, the problem is that when I close the window, the popup doesn't seem to open, and the lock remains in place. Again, this happens under IE, but not Opera. I would have tested it under Mozilla, but one of the Javascript operations (refering to a window's opener) didn't work.