Safe Script Tag Insertion

safeScriptInsertion.js

// When a script appends new SCRIPT tags to the HEAD or BODY, it can 
// run into serious trouble.  If it was originally included in the HEAD, the 
// HEAD might not have fully rendered when it fires, and the BODY isn't there yet.
// And if it's in the BODY, older browsers may blow chunks if it tries to append 
// SCRIPT tags to the HEAD.
//
// What seems to work:  be HEAD/BODY agnostic. Look for the first SCRIPT tag on the 
// page and insert before it.

var runScript = function(url) {    
   var script = document.createElement('SCRIPT');
   script.src = url;
   script.type = 'text/javascript';
   script.charset = 'UTF-8';
   var index = document.getElementsByTagName('SCRIPT')[0];
   index.parentNode.insertBefore(script, index);
};