mass种子模块之domready

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 function fireReady() {

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 function doScrollCheck() {

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.