在寫JS的過程中，為了調試我們常常會寫很多 console.log、console.info、console.group、console.warn、console.error代碼來查看JS的運行情況，但發布時又因為IE不支持console，又要去掉這些代碼，一不小心就會出錯。
本文分享自己昨晚寫的一個console類來試圖解決這一問題。當然，更好的做法是把測試代碼分開寫，那樣就不會有這個問題。
解決思路
如何解決IE下不兼容的問題呢，那就是我們自己定義一個console類來覆蓋浏覽器提供的console功能，這樣只要在頁面中引用此JS文件就可以了。
另外，此類還提供了查看輸出的調試信息功能，console 定義了哪些功能呢，我們可以在這裡看到：http://getfirebug.com/wiki/index.php/Console_API，我們可以看到這裡提供了很多方法，我們常用的有 console.log、console.info、console.group、console.warn、console.error、console.profile、console.time，最後兩個是分析代碼性能的，比較復雜，本文沒有實現。
代碼解析
第一步，當然是搭一個結構，覆蓋浏覽器(firebug、chrome)提供的console功能，這樣直接引用此JS文件即可保證浏覽器(主要是IE)中不出錯：
復制代碼 代碼如下:
console
var console={
assert:function(){
},
clear:function(){
},
count:function(){
},
debug:function(){
},
dir:function(){
},
dirxml:function(){
},
error:function(){
},
exception:function(){
},
group:function(name){
},
groupCollapsed:function(){
},
groupEnd:function(){
},
info:function(){
},
log:function(){
},
memoryProfile:function(){
},
memoryProfileEnd:function(){
},
profile:function(){
},
profileEnd:function(){
},
table:function(){
},
time:function(){
},
timeEnd:function(){
},
timeStamp:function(){
},
trace:function(){
},
warn:function(){
}
};
第二步，實現 console.log方法。在所實現的幾個方法中這個是最復雜的。
從firebug的API中我們可以看到，console.log不僅僅可以輸出信息，還提供了類似 string.Format的功能，直接引用原文如下：
Here is the complete set of patterns that you may use for string substitution:
復制代碼 代碼如下:
console.log('%cTest output', 'color:white; background-color:blue');
運行後的結果是這樣的：
這裡%c也可以跟 %s、%d等混用。
所以，在代碼中我直接用replace進行替換，由於JS中的replace默認只替換第一個匹配項，這裡剛好，代碼如下：
復制代碼 代碼如下:
var args=Array.prototype.slice.call(arguments);
if(args.length>1){
var i=1,hasstyle=false;
if(args[0].indexOf("%c")==0){
args[0]=args[0].replace(/%c/,"");
i=2;
hasstyle=true;
}
for(;i<args.length;i++){
if(/%s|%d|%i|%o/.test(args[0])){
args[0]=args[0].replace(/%s|%d|%i|%o/,args[i]);
}
else{
break;
}
}
if(i<args.length){
args[0]=args[0]+" "+args.slice(i).join(" ");
}
if(hasstyle){
consoleHelper.showlog(args[0],args[1]);
}
else{
consoleHelper.showlog(args[0]);
}
}
else if(args.length==1){
if(arguments[0] instanceof Array){
consoleHelper.showlog("["+args[0]+"]");
}
else if(arguments[0] instanceof Function){
consoleHelper.showlog(args[0],null,"console_log_function");
}
else{
consoleHelper.showlog(args[0]);
}
}
else{
consoleHelper.showlog("");
}
由於console.log可以接受多個參數，且個數不確定，所以這裡直接沒有寫形參。對於%c雖然firebug中寫在中間也是有效的，這裡為了簡單直接只對寫在開頭的有效。代碼中先把參數轉換為數組，然後對數組進行分情況處理。
當參數個數大於1時，對後面的參數用replace進行替換，然後把剩下的參數連接(join)起來進行輸出。
當參數個數為1時，還要分兩種情況，一是數組，二是方法。對於數組，按firebug中的格式，在兩端加中括號，對於函數，把字的顏色變為綠色
當參數個數為0時，直接輸出空字符串
後面的consoleHelper.showlog是為了輸出方便另外寫的一個方法，在這個方法中把各種調試信息的結果顯示在頁面上的一個div(如果存在)中。
其他幾個方法的思路跟這個差不多，只是樣式不同，功能比這個簡單，直接把參數連接起來輸出即可。
整個console類代碼如下：
復制代碼 代碼如下:
console全部代碼
var console={
assert:function(){
},
clear:function(){
},
count:function(){
},
debug:function(){
},
dir:function(){
},
dirxml:function(){
},
error:function(){
var args=Array.prototype.slice.call(arguments);
consoleHelper.showerror(args.join(" "));
},
exception:function(){
},
group:function(name){
consoleHelper.showgroup(name);
},
groupCollapsed:function(){
},
groupEnd:function(){
},
info:function(){
var args=Array.prototype.slice.call(arguments);
if(args.length==1){
if(arguments[0] instanceof Array){
consoleHelper.showinfo("["+args[0]+"]");
}
else if(arguments[0] instanceof Function){
consoleHelper.showinfo(args[0],"console_log_function");
}
else{
consoleHelper.showinfo(args[0]);
}
}
else{
consoleHelper.showinfo(args.join(" "));
}
},
log:function(){
var args=Array.prototype.slice.call(arguments);
if(args.length>1){
var i=1,hasstyle=false;
if(args[0].indexOf("%c")==0){
args[0]=args[0].replace(/%c/,"");
i=2;
hasstyle=true;
}
for(;i<args.length;i++){
if(/%s|%d|%i|%o/.test(args[0])){
args[0]=args[0].replace(/%s|%d|%i|%o/,args[i]);
}
else{
break;
}
}
if(i<args.length){
args[0]=args[0]+" "+args.slice(i).join(" ");
}
if(hasstyle){
consoleHelper.showlog(args[0],args[1]);
}
else{
consoleHelper.showlog(args[0]);
}
}
else if(args.length==1){
if(arguments[0] instanceof Array){
consoleHelper.showlog("["+args[0]+"]");
}
else if(arguments[0] instanceof Function){
consoleHelper.showlog(args[0],null,"console_log_function");
}
else{
consoleHelper.showlog(args[0]);
}
}
else{
consoleHelper.showlog("");
}
},
memoryProfile:function(){
},
memoryProfileEnd:function(){
},
profile:function(){
},
profileEnd:function(){
},
table:function(){
},
time:function(){
},
timeEnd:function(){
},
timeStamp:function(){
},
trace:function(){
},
warn:function(){
var args=Array.prototype.slice.call(arguments);
if(args.length==1){
if(arguments[0] instanceof Array){
consoleHelper.showwarn("["+args[0]+"]");
}
else if(arguments[0] instanceof Function){
consoleHelper.showwarn(args[0],"console_log_function");
}
else{
consoleHelper.showwarn(args[0]);
}
}
else{
consoleHelper.showwarn(args.join(" "));
}
}
};
consoleHelper代碼如下：
復制代碼 代碼如下:
var consoleHelper={
showlog:function(val,style,cla){
if(cla){
cla="console_log "+cla;
}
else{
cla="console_log";
}
this.show(val,style,cla);
},
showinfo:function(val,cla){
if(cla){
cla="console_info "+cla;
}
else{
cla="console_info";
}
this.show(val,null,cla);
},
showwarn:function(val,cla){
if(cla){
cla="console_warn "+cla;
}
else{
cla="console_warn";
}
this.show(val,null,cla);
},
showerror:function(val){
this.show(val,null,"console_error");
},
showgroup:function(val){
if(!val){
val="";
}
this.show(val+":",null,"console_group");
},
show:function(val,style,cla){
if(document.getElementById("showconsole")){
var div=document.createElement("div");
if(div.setAttribute){
if(style){
div.setAttribute("style",style);
}
}
else{
if(style){
div=document.createElement("<div style="+style+">");
}
}
if(cla){
div.className=cla;
}
var oText=document.createTextNode(val);
div.appendChild(oText);
document.getElementById("showconsole").appendChild(div);
}
}
};
注：如果想在頁面中看到調試信息，直接在頁面上添加一個id 為 showconsole 的隱藏的div即可。
樣式(盡量跟FireBug保持一致)：
復制代碼 代碼如下:
.console_log{
border:1px solid #CCC;
color:#333;
padding:0px 5px;
min-height:24px;
line-height:24px;
margin-bottom:-1px;
}
.console_info{
border:1px solid #CCC;
color:#333;
padding:0px 5px;
min-height:24px;
line-height:24px;
margin-bottom:-1px;
background: url("data:image/png;base64,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") no-repeat scroll 0 1px #EBF5FF;
padding-left:30px;
}
.console_warn{
border:1px solid #CCC;
color:#333;
padding:0px 5px;
min-height:24px;
line-height:24px;
margin-bottom:-1px;
background: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABYAAAAWCAYAAADEtGw7AAAD/ElEQVQ4jbWUX2gcVRSHv3tndmaTTbJJSJNWaXVNCUVjFbEWlb4U9aEYjRYURHwqKIIvgqX0oZEi+CIqCBYUjVhE8aW0xAfxSQhpSaVqETWpDdhtbWvS/NvZ2dm5c+/xIUmTdlN86oUDw71zvnvu7xx+SkS4HUvfFirg3/Lk/Lcw9tp2l9lBE8ujzrBBaWK/iT+8UI+osPMHXpxKbpWu1pNCjnZtsXH6fm2xddAWd3iqow/d3I5YgyxegpnThHpqMiiq/Xpw/DjFvv8Huy86dtTn7PF6ftem4P7nULkmCAso7YEIklQQEbLyGeT8V66wITmsd75zWPe/IbcE2+HOu+vz2UlT3LMx2PYEKNAB5LY9gy50YzPDX99/wF1dnYgFO3cR+8sRCj3J6/6+hSNrwdebZ0+/rbI4+yjV/RuD3p34YUTYHhG2RmhtlyQCrF4gbI8IWiP89iJ667Mkc7yXfdp597pgd+bDHWkU7An6dhG2V8nlI7SLwEQgdjUjq6GyCE9HhMUq4ebN2KC32Rq7f31wJnspbtX5DQpNFbI1IW4NOAZTBVNFZVVyzTFBaTs2YTD9vDdY+e36uNlUHg96N6OJwdzU4pWKRcAmS5etNAkIu1upTbVsktpsCZi4AYx4PX5b01JFN6/lPZPW0GYeFq+CqYDS0HQH2m9BtxaRuNrdCFYkykVgwkZwMg1AdWGa5sppCL3Vs2oZOh5A6wznqDdIgbMTMjvRT2cJ1HKiOMiqpJdHubLQxJW/f2Nr3uMGJxCBhQmkNmsEf6oBLKK+swvX9nragBcCArYOOLzFYdpqn9EGtBVyDQ9yaYKrmfH8yz/ONFas88eyhdq7fmtzz2o9CvDwtjxNe74bcZbs3FG0tzolApi5CGc5onseXMWtfBTevDpvU4bS6XmcFcBbjd5XYPsB7H1vce4K1/dFPGwlwszXxlTxnm/WvuIGd/P7Bj4xEyceVurffbliEZVvQSnFzO8nuFw/ibMZTRoEjZgUV52nfq1eFpd7oeXVn+1aVoMJVYaf1HJp/HCuRQ4EbdpTuTx4wdJoIeAyxCTY2JAuMm5dsLd4cObizbqva5vTF/5EDz/2kO9lB3PNPOWFtC6bGzbFmhpnTaI+nsmVvgxeOpaWSqUGhhobG2NoaMibnJz0K5VKkKZpYK0NnHM5Eck9cqdqf/5e3d/RpLpqRuo//ePOfX1WLljBKKWM1tpordMgCNJCoZCWSiVz6NAh6xtjiOOYLMuUtVaLyEp4gH+qbOunyvbX5Y4pwAK+UkoAJyJORLS1VmdZpuI4VlEUrS/FyMiIGh0dpVwuq9nZWRXHMUmSKIB8Pi9hGNLV1SU9PT2ye/duBgYGGiD/AVNZApv23zD/AAAAAElFTkSuQmCC") no-repeat scroll 0 1px #FFFFC8;
padding-left:30px;
}
.console_error{
border:1px solid #CCC;
color:#FF0000;
padding:0px 5px;
min-height:24px;
line-height:24px;
margin-bottom:-1px;
background: url("data:image/png;base64,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") no-repeat scroll 0 1px #FFEBEB;
padding-left:30px;
}
.console_group{
margin-top:20px;
font-size:16px;
font-weight:bolder;
}
.console_log_function{
color:green;
}
這裡為了演示方便，三個小圖標直接用的是base64格式的圖片，就是上面代碼中的三個長字符串，大家用時可以換成圖片地址。
完整代碼：
復制代碼 代碼如下:
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<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title>自定義console</title>
<style type="text/css">
.console_log{
border:1px solid #CCC;
color:#333;
padding:0px 5px;
min-height:24px;
line-height:24px;
margin-bottom:-1px;
}
.console_info{
border:1px solid #CCC;
color:#333;
padding:0px 5px;
min-height:24px;
line-height:24px;
margin-bottom:-1px;
background: url("data:image/png;base64,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") no-repeat scroll 0 1px #EBF5FF;
padding-left:30px;
}
.console_warn{
border:1px solid #CCC;
color:#333;
padding:0px 5px;
min-height:24px;
line-height:24px;
margin-bottom:-1px;
background: url("data:image/png;base64,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") no-repeat scroll 0 1px #FFFFC8;
padding-left:30px;
}
.console_error{
border:1px solid #CCC;
color:#FF0000;
padding:0px 5px;
min-height:24px;
line-height:24px;
margin-bottom:-1px;
background: url("data:image/png;base64,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") no-repeat scroll 0 1px #FFEBEB;
padding-left:30px;
}
.console_group{
margin-top:20px;
font-size:16px;
font-weight:bolder;
}
.console_log_function{
color:green;
}
</style>
<script type="text/javascript">
var console={
assert:function(){
},
clear:function(){
},
count:function(){
},
debug:function(){
},
dir:function(){
},
dirxml:function(){
},
error:function(){
var args=Array.prototype.slice.call(arguments);
consoleHelper.showerror(args.join(" "));
},
exception:function(){
},
group:function(name){
consoleHelper.showgroup(name);
},
groupCollapsed:function(){
},
groupEnd:function(){
},
info:function(){
var args=Array.prototype.slice.call(arguments);
if(args.length==1){
if(arguments[0] instanceof Array){
consoleHelper.showinfo("["+args[0]+"]");
}
else if(arguments[0] instanceof Function){
consoleHelper.showinfo(args[0],"console_log_function");
}
else{
consoleHelper.showinfo(args[0]);
}
}
else{
consoleHelper.showinfo(args.join(" "));
}
},
log:function(){
var args=Array.prototype.slice.call(arguments);
if(args.length>1){
var i=1,hasstyle=false;
if(args[0].indexOf("%c")==0){
args[0]=args[0].replace(/%c/,"");
i=2;
hasstyle=true;
}
for(;i<args.length;i++){
if(/%s|%d|%i|%o/.test(args[0])) {
args[0]=args[0].replace(/%s|%d|%i|%o/,args[i]);
}
else{
break;
}
}
if(i<args.length){
args[0]=args[0]+" "+args.slice(i).join(" ");
}
if(hasstyle){
consoleHelper.showlog(args[0],args[1]);
}
else{
consoleHelper.showlog(args[0]);
}
}
else if(args.length==1){
if(arguments[0] instanceof Array){
consoleHelper.showlog("["+args[0]+"]");
}
else if(arguments[0] instanceof Function){
consoleHelper.showlog(args[0],null,"console_log_function");
}
else{
consoleHelper.showlog(args[0]);
}
}
else{
consoleHelper.showlog("");
}
},
memoryProfile:function(){
},
memoryProfileEnd:function(){
},
profile:function(){
},
profileEnd:function(){
},
table:function(){
},
time:function(){
},
timeEnd:function(){
},
timeStamp:function(){
},
trace:function(){
},
warn:function(){
var args=Array.prototype.slice.call(arguments);
if(args.length==1){
if(arguments[0] instanceof Array){
consoleHelper.showwarn("["+args[0]+"]");
}
else if(arguments[0] instanceof Function){
consoleHelper.showwarn(args[0],"console_log_function");
}
else{
consoleHelper.showwarn(args[0]);
}
}
else{
consoleHelper.showwarn(args.join(" "));
}
}
};
var consoleHelper={
showlog:function(val,style,cla){
if(cla){
cla="console_log "+cla;
}
else{
cla="console_log";
}
this.show(val,style,cla);
},
showinfo:function(val,cla){
if(cla){
cla="console_info "+cla;
}
else{
cla="console_info";
}
this.show(val,null,cla);
},
showwarn:function(val,cla){
if(cla){
cla="console_warn "+cla;
}
else{
cla="console_warn";
}
this.show(val,null,cla);
},
showerror:function(val){
this.show(val,null,"console_error");
},
showgroup:function(val){
if(!val){
val="";
}
this.show(val+":",null,"console_group");
},
show:function(val,style,cla){
if(document.getElementById("showconsole")){
var div=document.createElement("div");
if(div.setAttribute){
if(style){
div.setAttribute("style",style);
}
}
else{
if(style){
div=document.createElement("<div style="+style+">");
}
}
if(cla){
div.className=cla;
}
var oText=document.createTextNode(val);
div.appendChild(oText);
document.getElementById("showconsole").appendChild(div);
}
}
};
window.onload=function(){
console.group("log");
console.log('%c a %s This is red text on a green background','color:red; background-color:#EEE');
console.log("The %%s jumped over %d tall buildings",1, "abc",1);
console.log("I am %s and I have:", "abc", "bcd","cde");
console.log("abc",1);
console.log([1,2,3,4,5]);
console.log();
console.log(test);
console.group("info");
console.info('%c a %s This is red text on a green background','color:red; background-color:#EEE');
console.info("The %%s jumped over %d tall buildings",1, "abc",1);
console.info("I am %s and I have:", "abc", "bcd","cde");
console.info("abc",1);
console.info([1,2,3,4,5]);
console.info();
console.info(test);
console.group("warn");
console.warn('%c a %s This is red text on a green background','color:red; background-color:#EEE');
console.warn("The %%s jumped over %d tall buildings",1, "abc",1);
console.warn("I am %s and I have:", "abc", "bcd","cde");
console.warn("abc",1);
console.warn([1,2,3,4,5]);
console.warn();
console.warn(test);
console.group("error");
console.error('%c a %s This is red text on a green background','color:red; background-color:#EEE');
console.error("The %%s jumped over %d tall buildings",1, "abc",1);
console.error("I am %s and I have:", "abc", "bcd","cde");
console.error("abc",1);
console.error([1,2,3,4,5]);
console.error(test);
}
function test(){
alert("abc");
alert("abc");
alert("abc");
alert("abc");
alert("abc");
alert("abc");
alert("abc");
alert("abc");alert("abc");
}
</script>
</head>
<body>
<h1>自定義console(Artwl.cnblogs.com)</h1>
<div id="showconsole"></div>
</body>
</html>
小結
寫這個JS一方面是工作中有這方面的需求，另外也是因為在博問中看到有人問 JavaScript中如何獲得console.log的值？ ，前段時間有個國外學編程網站可以把console.log的結果直接顯示在頁面上，不知道是不是用了本文類似的方案。
歡迎大家留言討論。
作者：Artwl