Web front-end development also needs logs_javascript skills

For example, IE6 is not so rich on it, which brings a lot of pain to program debugging, so real-time log output is a good choice to know where the program is covered. It is necessary even on advanced browsers. It is much faster and easier than debugging the program to determine whether the corresponding business code has been executed. Well, let me introduce to you a method I use in my spare time. Written debugging information output tool.
Code above:

Copy code The code is as follows:

(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 = "调试信息控制台
";
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;
}
}
});
})();

上面代码调用也相当的简单

复制代码 代码如下:

assert("debug","调试信息");

The corresponding log will appear on the page.
This log output part of the code is taken from a unit test module of the Jquery author.