Defer works, but in IE it tells the browser if it should continue rendering
elements once the external script file is loaded.

Use: <script language = "myJS.js" defer> 

or 

create a conditional statement using:  readyState

if (document.all.ExternalScript.readyState == "unitialized")
{
	//don't load even't 
}
	else
{
	//load event
}