Асинхронный загрузчик скриптов с обратным вызовом онлайн урок.




var Loader = function () { }
Loader.prototype = {
require: function (scripts, callback) {
this.loadCount = 0;
this.totalRequired = scripts.length;
this.callback = callback;

for (var i = 0; i < scripts.length; i++) {
this.writeScript(scripts[i]);
}
},
loaded: function (evt) {
this.loadCount++;

if (this.loadCount == this.totalRequired && typeof this.callback == 'function') this.callback.call();
},
writeScript: function (src) {
var self = this;
var s = document.createElement('script');
s.type = "text/javascript";
s.async = true;
s.src = src;
s.addEventListener('load', function (e) { self.loaded(e); }, false);
var head = document.getElementsByTagName('head')[0];
head.appendChild(s);
}
}

# Применение

var l = new Loader();
l.require([
"example-script-1.js",
"example-script-2.js"],
function() {
// Callback
console.log('All Scripts Loaded');
});