web前端開發也需要日志_javascript技巧

如IE6,在他上面還不那么富饒，給程序調試帶來的很大的痛苦啊，所以日志即時輸出是一個不錯的選擇，可以知道程序覆蓋到了哪里。即是在先進的瀏覽器上也是很有必要的，他比去調試程序來確定相應的業務代碼有沒有執行到也快的多也容易的多，好了，下面來給大家介紹一個我業余時間寫的調試信息輸出工具。
上代碼：
代碼如下:
(function(){
var cache = [];
var el = null;
this.__debugLine = 1;
function parseObjToStr(obj){
if(obj.constructor == String){
return obj.toString();
}
var ret = [];
for(var o in obj){
if(typeof obj[o]!="function")
ret.push(o+":"+obj[o]);
}
return ret.join(",");
}
this.assert = function(flag,msg){
msg = {"number":1,"string":1,"boolean":1,"function":1,"undefined":1}[typeof msg]?msg:parseObjToStr(msg);
//Log.getInstance().debug(msg);
return;
var bgColor = this.__debugLine%2==0?"background-color:#F8F8F8":"background-color:#ffffff";
msg = flag=="debug"?String.format('

{1}

[{3}]:{4}

',
bgColor,this.__debugLine,"#333333",flag,msg):msg;
if(flag.constructor!=String)
msg = String.format('

{1}

[{3}]:{4}

',
bgColor,this.__debugLine,flag?"green":"red",flag?"PASS ":"FAIL ",msg);
this.__debugLine++;
if(cache!=null){
cache[cache.length] = msg;
}
else{
el.innerHTML += msg;
}
}
function applyStyle(el,style){
for(var pro in style){
el.style[pro] = style[pro];
}
}
addEvent(window,"load",function(){
return;
el = document.createElement("div");
var elStyle ={backgroundColor:"#ffffff",color:"#333333",border:"1px solid #dcdada",borderLeft:"0px solid #6CE26C",borderRight:"0px solid #6CE26C"
,lineHeight :"25px",textAlign:"left",listStyleType :"none",margin:"0px",maxHeight:"200px",overflow:"auto"};
var head = document.createElement("div");
var headStyle ={backgroundColor:"#fef5c5",lineHeight:"25px"};
head.innerHTML = "調試信息控制臺+
";
var wrap = document.createElement("div");
var wrapStyle ={overflow:"hidden",backgroundColor:"#ffffff",color:"#333333",border:"1px solid #C0C0C0","fontSize":"12px","margin":"5px",position:"fixed",left:"0px",bottom:"0px",width:"97%"};
var foot = document.createElement("div");
var footStyle ={padding:"0",textAlign:"left"};
foot.innerHTML = ">>>";
applyStyle(wrap,wrapStyle);
applyStyle(head,headStyle);
applyStyle(el,elStyle);
applyStyle(foot,footStyle);
wrap.appendChild(head);
wrap.appendChild(el);
wrap.appendChild(foot);
document.body.appendChild(wrap);
el.innerHTML = cache.join("");
cache = null;
function toggle(){
if(!this.hide){
el.style.display = "none";
foot.style.display = "none";
wrap.style.width = "200px";
this.hide = true;
}
else{
el.style.display = "";
foot.style.display = "";
wrap.style.width = "98%";
this.hide = false;
}
}
head.onclick = function(){
toggle.call(this);
}
head.onclick();
document.getElementById("console_eval").onkeydown = function(e){
e = e||window.event;
if(e.keyCode==13){
try{
eval.call(window,String.format("assert('debug',{0})",this.value));
}
catch(e){
assert("debug",e.message);
}
el.scrollTop = el.scrollHeight;
}
}
});
})();

上面代碼調用也相當的簡單
代碼如下:
assert("debug","調試信息");

頁面中就會出相應的日志。
該日志輸出部分代碼取自Jquery作者一個單元測試模塊。

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