It seems that the window.onload event is called prior to the loading of included js files. Its a bit hit and miss - sometimes the js is loaded in time and all works fine. Try it for yourself with 2 js files - the first file includes the second file and then uses a var that is in the second file. Firefox 2 works. Firefox 3 beta comes up with an error because the var is not defined … then try refresh a few times and it will work now and then.

function include_dom(script_filename, oCallback) {
var html_doc = document.getElementsByTagName('head').item(0);
var js = document.createElement('script');
js.setAttribute('language', 'javascript');
js.setAttribute('type', 'text/javascript');
js.setAttribute('src', script_filename);
if (oCallback != null){
// most browsers
js.onload = oCallback;
// IE 6 & 7
js.onreadystatechange = function() {
if (this.readyState == 'loaded') {
oCallback();
}
}
}
html_doc.appendChild(js);
return false;
}

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