Simple Javascript & CSS Loader

jsloader.js

var Loader = {};

(function (app) {
    app.LinkCSS = function (href) {
        //Link the stylesheet needed.
        var headID = document.getElementsByTagName("head")[0];
        var cssNode = document.createElement('link');
        cssNode.type = 'text/css';
        cssNode.rel = 'stylesheet';
        cssNode.href = href;
        cssNode.media = 'screen';
        headID.appendChild(cssNode);
    }

    /** This loads a script asynchronously and then calls a callback function if supplied.
     *  Loader.getScript('stringURL',callback)
     *  Loader.getscript({js: 'stringURL', css: 'stringURL'},callback)   
     */
    app.getScript = function (url, success) {

        var script = document.createElement('script');
        script.src = url.js || url;

        var head = document.getElementsByTagName('head')[0],
            done = false;

        // Attach handlers for all browsers
        script.onload = script.onreadystatechange = function () {
            if (!done && (!this.readyState || this.readyState == 'loaded' || this.readyState == 'complete')) {
                done = true;
                // callback function provided as param
                if (typeof success === 'function') {
                    success();
                }
                script.onload = script.onreadystatechange = null;
                head.removeChild(script);
            };
        };

        head.appendChild(script);

        if (url.css) {
            app.LinkCSS(url.css);
        }
    }
})(Loader);