IE6789浏览器使用console.log类似的方法输出调试内容但又不影响页面正常运行

问题来源：外网IE下，触发js报错。经检测，未清除console造成。清除console后，解决。

问题原因：console.log 原先是 Firefox 的“专利”，严格说是安装了 Firebugs 之后的 Firefox 所独有的调试“绝招”。 这一招，IE8 学会了，不过用起来比 Firebugs 麻烦，只有在开启调试窗口(F12)的时候，console.log 才能出结果，不然就报错。
详细出处参考：http://www.jb51.net/article/30469.htm

解决问题：http://q.cnblogs.com/q/33770/  http://icant.co.uk/sandbox/fauxconsole/
1：Complete cross-browser console.log()，兼容几乎所有浏览器的代码

/ Tell IE9 to use its built-in console
 
if (Function.prototype.bind && console && typeof console.log == "object") {
 
["log","info","warn","error","assert","dir","clear","profile","profileEnd"]
 
    .forEach(function (method) {
 
        console[method] = this.call(console[method], console);
 
    }, Function.prototype.bind);
 
}
 
// log() -- The complete, cross-browser (we don't judge!) console.log wrapper for his or her logging pleasure
 
if (!window.log) {
 
window.log = function () {
 
log.history = log.history || [];  // store logs to an array for reference
 
log.history.push(arguments);
 
    // Modern browsers
 
    if (typeof console != 'undefined' && typeof console.log == 'function') {
 
        // Opera 11
 
        if (window.opera) {
 
            var i = 0;
 
            while (i < arguments.length) {
 
                console.log("Item " + (i+1) + ": " + arguments[i]);
 
                i++;
 
            }
 
        }
 
        // All other modern browsers
 
        else if ((Array.prototype.slice.call(arguments)).length == 1 && typeof Array.prototype.slice.call(arguments)[0] == 'string') {
 
            console.log( (Array.prototype.slice.call(arguments)).toString() );
 
        }
 
        else {
 
            console.log( Array.prototype.slice.call(arguments) );
 
        }
 
    }
 
    // IE8
 
    else if (!Function.prototype.bind && typeof console != 'undefined' && typeof console.log == 'object') {
 
        Function.prototype.call.call(console.log, console, Array.prototype.slice.call(arguments));
 
    }
 
    // IE7 and lower, and other old browsers
 
    else {
 
        // Inject Firebug lite
 
        if (!document.getElementById('firebug-lite')) {
 
            // Include the script
 
            var script = document.createElement('script');
 
            script.type = "text/javascript";
 
            script.id = 'firebug-lite';
 
            // If you run the script locally, point to /path/to/firebug-lite/build/firebug-lite.js
 
            script.src = 'https://getfirebug.com/firebug-lite.js';
 
            // If you want to expand the console window by default, uncomment this line
 
            //document.getElementsByTagName('HTML')[0].setAttribute('debug','true');
 
            document.getElementsByTagName('HEAD')[0].appendChild(script);
 
            setTimeout(function () { log( Array.prototype.slice.call(arguments) ); }, 2000);
 
        }
 
        else {
 
            // FBL was included but it hasn't finished loading yet, so try again momentarily
 
            setTimeout(function () { log( Array.prototype.slice.call(arguments) ); }, 500);
 
        }
 
    }
 
}
 
}

2：专门为ie下调试js用，Faux Console，使用方法:

2.1.引入css文件，及js文件

<link type="text/css" rel="stylesheet" href="fauxconsole.css" />

<script type="text/javascript" src="fauxconsole.js"></script>

//fauxconsole.css
#fauxconsole{
 position:absolute;
 top:;
 right:;
 width:300px;
 border:1px solid #999;
 font-family:courier,monospace;
 background:#eee;
 font-size:10px;
 padding:10px;
}
html>body #fauxconsole{
 position:fixed;
}
#fauxconsole a{
 float:right;
 padding-left:1em;
 padding-bottom:.5em;
 text-align:right;
}

//fauxconsole.js
/* Faux Console by Chris Heilmann http://wait-till-i.com */
 if(!window.console){
         var console={
             init:function(){
                 console.d=document.createElement('div');
                 document.body.appendChild(console.d);
                 var a=document.createElement('a');
                 a.href='javascript:console.hide()';
                 a.innerHTML='close';
                 console.d.appendChild(a);
                 var a=document.createElement('a');
                 a.href='javascript:console.clear();';
                 a.innerHTML='clear';console.d.appendChild(a);
                 var id='fauxconsole';
                 if(!document.getElementById(id)){console.d.id=id;}
                 console.hide();
                 },hide:function(){
                     console.d.style.display='none';
                 },show:function(){
                     console.d.style.display='block';
                 },log:function(o){
                     console.d.innerHTML+='<br/>'+o;console.show();
                 },clear:function(){
                     console.d.parentNode.removeChild(console.d);
                     console.init();
                     console.show();
                 },/*Simon Willison rules*/
                 addLoadEvent:function(func){
                     var oldonload=window.onload;
                     if(typeof window.onload!='function'){
                         window.onload=func;
                     }else{
                         window.onload=function(){
                             if(oldonload){
                                 oldonload();
                             }
                             func();
                         }
                     };
                 }
         };
         console.addLoadEvent(console.init);
 }

• It tests if there is a console object defined - if there is one this means your browser has a console and the script does nothing else.

//看看有没有console对象定义,如果浏览器定义了console,嘛也不做。

• If console is undefined, the script creates a new console object and adds a DIV to the body of the document.

//如果没有定义console,fauxconsole.js创建一个console对象，同时在 body中增加一个DIV.

• It adds a close and clear link to that DIV which allow you to hide or wipe the console.

//给新增的DIV增加一个关闭，清除链接，这样，你就能隐藏或者展开console对话。

• It provides you with the following methods:

//JS提供了以下功能：

• console.log(message) - adds message to the log //console.log(message)输出消息
• console.show() - shows the console //console.show() 展示console
• console.hide() - hides the console//console.hide()隐藏console

• The script adds the ID fauxconsole to the DIV (unless there is another element with that ID) and you can style the console using that. The preset CSS fauxconsole.css is pretty basic and shows the console as a grey box fixed to the top right corner of the viewport.

//JS代码增加了一个ID fauxconsole 给那个新增的DIV（文档中不要有重复的ID，若重复，必须更换另一个ID名），通过定义fauxconsole，控制console.在fauxconsole.css中，默认console box固定在浏览器可见区域右上角，背景为灰色。