While testing Illyriad we found that over time the browsers IE7 and IE8 leak memory on Ajax calls using JQuery 1.4.
If you make a lot of ajax calls without changing page this can build up quite quickly and start causing issues. This is caused by the onreadystatechange event not being detached and IE not garbage-collecting the associated memory.
To fix this, locate these lines in the source JQuery file; already kindly annotated with “Stop memory leaks”:
[code lang=”js” firstline=”6019″ title=”Original jquery-1.4.4.js”]
// Stop memory leaks
if ( s.async ) {
xhr = null;
}
[/code]
Add in these extra lines to change them to the following (we detach the abort event also for good measure):
[code lang=”js” firstline=”6019″ title=”Modified jquery-1.4.4.js”]
// Stop memory leaks
if ( s.async ) {
try {
xhr.onreadystatechange = null;
xhr.abort = null;
} catch (ex) { };
xhr = null;
}
[/code]
Don’t forget to minify your jquery file before including it. [We prefer using UglifyJS]
Also rename it slightly so users with cached versions pick up the new file
e.g. jquery-1.4.4a-min.js