总结：由于IE6/7/8不支持DOMContentLoaded事件，虽然它支持onreadystatechange事件，但是readyState=complete几乎和onload事件一样，需要等页面中的外部资源加载完后才触发，想要尽快可采用doScroll检测法（仅在非iframe下有效）

1 var turbo = turbo ||{};2 var W3C = document.addEventListener ? true : false;3 var doc = document, html =document.documentElement;4 var readyList =[];5 turbo.ready = function(fn) {6     //不管是哪个分支，只要触发过一次ready事件readyList就会为null
7     if(readyList) {8 readyList.push(fn);9     } else{10 fn();11 }12 };13 functionfireReady() {14     if (readyList &&readyList.length) {15         for (var i = 0, len = readyList.length; i < len; i++) {16             var fn =readyList[i];17 fn();18 }19 }20     readyList = null;21 }22
23 functiondoScrollCheck() {24     try{25         html.doScroll('left');26 fireReady();27     } catch(e) {28         setTimeout(doScrollCheck, 50);29 }30 }31
32 var ready = W3C ? "DOMContentLoaded" : "readystatechange";33 //由于firefox3.6不支持readyState，则在不支持readyState的时需手动赋值给它
34 if (!doc.readyState) {35     //如果doc.body已存在则说明domcontentloaded了，将doc.readySate设置为complete
36     var readyState = doc.readySate = doc.body ? "complete" : "loading";37 }38
39 if (doc.readyState == 'complete') {40 fireReady();41 } else{42     $.bind(doc, ready, function() {43         if (W3C || doc.readyState == 'complete') {44 fireReady();45             //firefox3.6,我觉得这里设不设置都行，因为这里已经用不到了doc.readyState了
46             if(readyState) {47                 doc.readyState = 'complete';48 }49 }50 })51     //ie下使用doScroll，尽量提前触发ready，此方法只在非iframe下的页面有效
52     var top = false;53     try{54         top = doc.frameElement == null &&doc.documentElement;55     } catch(e) {}56     if (top &&top.doScroll) {57 doScrollCheck();58 }59 }

有点看不懂mass里最后一段调用doScrollCheck的代码，故采用的jQuery的写法.