window.onload加載完畢的問題及解決方案（下）

接上篇，其它方法：

一、在IE中還可以在onreadystatechange事件裏進行判斷

http://www.thefutureoftheweb.com/blog/adddomloadevent

這裏有Jesse Skinner寫了一段獨立的腳本函數來解決各種瀏覽器的onload問題， adddomloadevent.js。

 

代碼引用如下

/* * (c)2006 Jesse Skinner/Dean Edwards/Matthias Miller/John Resig * Special thanks to Dan Webb's domready.js Prototype extension * and Simon Willison's addLoadEvent * * For more info, see: * http://www.thefutureoftheweb.com/blog/adddomloadevent * http://dean.edwards.name/weblog/2006/06/again/ * http://www.vivabit.com/bollocks/2006/06/21/a-dom-ready-extension-for-prototype * http://simon.incutio.com/archive/2004/05/26/addLoadEvent * * * To use: call addDOMLoadEvent one or more times with functions, ie: * * function something() { * // do something * } * addDOMLoadEvent(something); * * addDOMLoadEvent(function() { * // do other stuff * }); * */ addDOMLoadEvent = (function(){ // create event function stack var load_events = [], load_timer, script, done, exec, old_onload, init = function () { done = true; // kill the timer clearInterval(load_timer); // execute each function in the stack in the order they were added while (exec = load_events.shift()) exec(); if (script) script.onreadystatechange = ''; }; return function (func) { // if the init function was already ran, just run this function now and stop if (done) return func(); if (!load_events[0]) { // for Mozilla/Opera9 if (document.addEventListener) document.addEventListener("DOMContentLoaded", init, false); // for Internet Explorer /*@cc_on @*/ /*@if (@_win32) document.write("<script id=__ie_onload defer src="//0" mce_src="http://0"><//scr"+"ipt>"); script = document.getElementById("__ie_onload"); script.onreadystatechange = function() { if (this.readyState == "complete") init(); // call the onload handler }; /*@end @*/ // for Safari if (/WebKit/i.test(navigator.userAgent)) { // sniff load_timer = setInterval(function() { if (/loaded|complete/.test(document.readyState)) init(); // call the onload handler }, 10); } // for other browsers set the window.onload, but also execute the old window.onload old_onload = window.onload; window.onload = function() { init(); if (old_onload) old_onload(); }; } load_events.push(func); } })();

 

 二、另外還有在IE中的doScroll的，這是種方法只對IE有作用，而且它是一種hack方法。

 

在MSDN:About Element Behaviors 我們可以看到

When the ondocumentready event fires, the document has been completely parsed and built. Initialization code should be placed here if the component needs to navigate the primary document structure. The ondocumentready event notifies the component that the entire page is loaded, and it fires immediately before the onload event fires in the primary document.

A few methods, such as doScroll, require the primary document to be completely loaded. If these methods are part of an initialization function, they should be handled when the ondocumentready event fires.

 

 http://javascript.nwbox.com/IEContentLoaded/

 iecontentloaded.js

/* * * IEContentLoaded.js * * Author: Diego Perini (diego.perini at gmail.com) NWBOX S.r.l. * Summary: DOMContentLoaded emulation for IE browsers * Updated: 05/10/2007 * License: GPL/CC * Version: TBD * */ // @w window reference // @fn function reference function IEContentLoaded (w, fn) { var d = w.document, done = false, // only fire once init = function () { if (!done) { done = true; fn(); } }; // polling for no errors (function () { try { // throws errors until after ondocumentready d.documentElement.doScroll('left'); } catch (e) { setTimeout(arguments.callee, 50); return; } // no errors, fire init(); })(); // trying to always fire before onload d.onreadystatechange = function() { if (d.readyState == 'complete') { d.onreadystatechange = null; init(); } }; }

 

 

在jQuery的源碼中，針對Mozilla, Opera 和webkit用的是DOMContentLoaded，也就是上一篇中第一種；

而對IE用的是doScroll的方法。