Load a JS or CSS file dynamically

gistfile1.js

var loadResource = function (filename, filetype){
	var loadedResource = undefined;
	if (filetype === "js"){ //if filename is a external JavaScript file
		loadedResource=document.createElement('script');
		loadedResource.setAttribute("type","text/javascript");
		loadedResource.setAttribute("src", filename);
	}
	else if (filetype === "css"){ //if filename is an external CSS file
		loadedResource=document.createElement("link");
		loadedResource.setAttribute("rel", "stylesheet");
		loadedResource.setAttribute("type", "text/css");
		loadedResource.setAttribute("href", filename);
	}
	if (typeof loadedResource !== undefined) {
		document.getElementsByTagName("head")[0].appendChild(loadedResource)
	}
};


var unLoadResource = function (filename, filetype){
    var targetElement = (filetype === "js")? "script" : (filetype === "css")? "link" : "none";
    var targetAttr = (filetype === "js")? "src" : (filetype === "css")? "href" : "none";
    var allSuspects = document.getElementsByTagName(targetElement);
    for (var i=allSuspects.length; i>=0; i--){ //search backwards for matching elements to remove
        if (allSuspects[i] && allsuspects[i].getAttribute(targetAttr) !== null && allSuspects[i].getAttribute(targetAttr).indexOf(filename) !== -1) {
            allSuspects[i].parentNode.removeChild(allSuspects[i]) //remove element by calling parentNode.removeChild();
        }
    }
};


// http://stackoverflow.com/questions/9425910/load-and-unload-javascript-at-runtime