/** * JS 加载到顶部 * @param {String} url * @param {Boolean} 请求并加载 * @param {Function} fn * @return {Boolean} */function requireJs(url, multi, fn) {    if (typeof multi == ‘function‘) {        var _temp = fn;        fn = multi;        multi = _temp;    }    var ss = document.getElementsByTagName(‘script‘);    var loaded = false;    for (var i = 0; i < ss.length; i++) {        if (ss[i].src && ss[i].getAttribute(‘src‘) == url) {            loaded = true;            break;        }    }    if (loaded) {        if (fn && typeof fn != ‘undefined‘ && fn instanceof Function){            fn();            return false;        }     }    var s = document.createElement(‘script‘),    b = false;    s.setAttribute(‘type‘, ‘text/javascript‘);    if (multi) {        this.loadJs = fn;        var noArg = url.indexOf(‘?‘) == -1;        s.setAttribute(‘src‘, url + (noArg?‘?‘:‘&‘) + ‘callback=WYSIWYG.loadJs‘);    } else {        s.setAttribute(‘src‘, url);        s.onload = s.onreadystatechange = function () {            if (!b && (!this.readyState || this.readyState == ‘loaded‘ || this.readyState == ‘complete‘)) {                b = true;                if (fn && typeof fn != ‘undefined‘ && fn instanceof Function) fn();            }        };    }    document.getElementsByTagName(‘head‘)[0].appendChild(s);}