function loadScript(url, callback) {

	if ( isFound(url) ) { return false; }

    var script = document.createElement("script");
    script.type = "text/javascript";

	if (script.readyState) {  //IE
		script.onreadystatechange = function() {
			if (script.readyState == "loaded" ||
				script.readyState == "complete") {
				script.onreadystatechange = null;
				callback();
			}
		};
	} else {  //Others
		script.onload = function() {
			callback();
		};
	}

	script.src = url;
	document.getElementsByTagName("head")[0].appendChild(script);
}

function isFound(url) {

	if (url.indexOf("http://") != -1) {
		var tmp = url.replace("http://", "");
		url = tmp.substring(tmp.indexOf("/"), tmp.length);
	}
	var scripts = document.getElementsByTagName("script");
	for (var i=0; i<scripts.length; i++) {
		var script = scripts[ i ];
		var script_url = script.src;
		if (script_url != "" && script_url.indexOf("http://") != -1) {
			var tmp = script_url.replace("http://", "");
			script_url = tmp.substring(tmp.indexOf("/"), tmp.length);
			if ( script_url == url ) {
				//console.log("[load.js] Script "+script_url+" matched into <script> tags: not loaded.");
				return true;
			}
		}
	}

	return false;
}