Create and Destroy
January 19, 1999
Create and destroy -- spawning the pop up window
and cleaning up after it.
function popIt()
{ popWin=window.open
("popups.html","PopUp",
"toolbar = no,
location = no,
directories = no,
status = no,
menubar = no,
scrollbars = no,
resizable = yes,
dependent = yes,
alwaysRaised = yes,
width = 250,
height = 100");
popWin.resizeTo(0,0);self.focus();}
function cleanUp()
{ if(!popWin.closed) {popWin.close();} }
//startup script
if (popAble) {
crossBrowser();
popIt();
self.focus();
window.onunload = function (e) {cleanUp()};
}
// end hiding code -->
</script>
<!-- end of pop up code -->
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When the client's original page loads, embedded with
the mission control script, it launches the popIt()
function as called by the statement in the "startup
script" section above. Very simply, popIt()
spawns the menu window and, by bringing focus to the main
browser window, effectively hides the menu. Resizing
the spawned window to 0 by 0 is only effective in Internet
Explorer, which minimized the window off the desktop;
Navigator simply ignores the request because it refuses
to size a window smaller than 100 by 100 pixels. Notice
in the window.open() parameters that the feature
dependent is set to yes. This causes the spawned
menu window to be a "dependent" window which,
as its namesake implies, is not totally independent.
Specifically,
in Netscape,
a dependent window will close when its parent window
closes. According to the
Internet Explorer developer documentation,
a dependent window should not contain
a close gadget or appear on the Windows taskbar -- however,
it does both because the dependent feature is apparently
broken or not implemented in Internet Explorer 4 (moral:
don't believe everything you read!).
Recall that the boolen popAble is only true if
the browser is version 4+ and running in Windows, and
so this check prevents the mission control script from
attempting to execute on an inappropriate platform.
Good etiquette suggests that it's proper to clean up
after oneself and DHTML is no exception. Should the user
leave the page which spawned the pop-up menu window we
should be sure to get rid of the spawned window. The function
cleanUp() does just that, and is called via an
onUnload event handler set for the page in the final line
of the startup script.
Action Hero
DHTML Pop-Up Menus: A Parable of Triumph and Loss (Based on a True Story)
Rigging the imagemap to trigger the pop-ups.
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