in Hacking

Closing an IE popup two times while busy with Ajax request hangs IE

Closing an IE popup (twice) while a XmlHttpRequest is running, uses up all available connections.

To reproduce this:
- create a slow XmlHttpRequest (xhr). (Running about a minute or so)
- Open a popup window which executes this xhr. Close it while it's still running
- Open this same popup again. (Second request). Directly close it while the xhr is running.
- Open another popup... et voila... IE Hangs..

This problem is what I was experiencing. After hours of frustrations we found a workaround:
In the onunload of the body tag you must call the "open" method on the same XmlHttpRequest object.
The call of "open" disconnects and stops the old request. Appearently abort doesn't do this

Working code:

WARNING: This solution has only be tested with IE7!

Update 23-01-2008:

Solution for this problem with prototype is. Just put this code in an seperate javascript file. Include this file after prototype.js call iefix_runGarbageControl() in the onunload and the bug is fixed ;-)

// IE TCP/IP Connection Leak FIX, with prototype
if( Prototype.Browser.IE )
var iefix_xhrs = new Array();
function iefix_runGarbageControl() {
for(var i=0; i

Update 24-04-2008:
Added: place 'iefix_runGarbageControl()' in the onunload

  1. Hi,

    I am running in the same problem in our application. We are using protoype as well, but I had trouble getting your fix to work. What version of prototype do you use?

    Thanks for the insight anyways.


  2. The code wasn’t complete, you should put the ‘iefix_runGarbageControl()’ in the onunload.

    Or use prototype’s Event.observe:
    (please check prototype’s documenation. I only tested it with a call to iefix_runGarbageControl() in the onUnload)

    I believe at the time we were using version 1.6

    Btw I never solved the problem completely. For most situation is works perfectly. But when you are using iframes in a page that are performing XHR’s you’re in trouble..

    Btw. There are many, many more IE memory/garbage collection related bugs. But you probably found out already ;-)

Comments are closed.