This is a simple little JavaScript snippet I wrote the other day that basically includes an external javascript file in an HTML page head section.

Its pretty straight forward,

  • it first gets a reference to the head tag.

  • Creates a script element using document.createElement

  • Sets the source/url of the file

  • sets the type of the script element to the correct mime type of "text/javascript"

  • Then sets the onload property of the script element to a callback function you supply. In i.e. it will check the onreadystatechange and execute the callback function you provide.

  • And finally it appends the script element to the head of the page

         *Load an externl JS file and append it to the head
        function require(file,callback){
            var head=document.getElementsByTagName("head")[0];
            var script=document.createElement('script');
            //real browsers
            //Internet explorer
            script.onreadystatechange = function() {
                if (_this.readyState == 'complete') {

Probably a million and one ways to do this but it works decently in I.E 7+,Firefox,Chrome,Safari and Opera