诡异的面向对象的进度条

#upPreg{
    width:360px;
    height:48px;
    position:absolute;
    top:0;left:0;right:0;bottom:0;
    margin:auto;
    z-index:1001;
}
#upPregA{
    width:100%;
    height:32px;
    position:absolute;
    top:5px;
    left:0px;
    overflow:hidden;
    border-radius:50px 0px 0px 50px;
}
#upPregBg{
    width:300px;
    height:18px;
    position:absolute;
    top:12px;left:0;
    border-radius:10px;
    background-color:#c2c2c2;
    z-index:999;
}

#upPregImg{
    width:300px;
    height:32px;
    position:absolute;
    top:0px;
    left:-270px;
    z-index:1001;
}
#bgDiv {
    position: fixed;
    top: 0px;
    background: black;
    opacity: 0.5;
    left: 0px;
    width: 100%;
    height: 100%;
    z-index: 100;    
    display:none;
}

$(function(){
    var ccc=new ceartPregress();//创建进度条
    ccc.start();
    setTimeout(function(){
        ccc.end();
    },4000)
    //ccc.end();    //进度完成
    
})
//构造进度条
function ceartPregress()
{
     this.oEle=document.getElementById("upPregImg");
     this.oDiv=document.getElementById("upPreg");
     this.oBg=document.getElementById("bgDiv");
     this.timer1=null;
     this.timer2=null;
}
//开始
ceartPregress.prototype.start=function()
{
    this.oDiv.style.display="block";
    this.oBg.style.display="block";
    var ele=this.oEle;
    var eft=-270;
    this.timer1=setInterval(function(){
        if(eft<-30){
            eft++;
            ele.style.left=eft+"px";
        }
        else{
            clearInterval(this);
        }
    },300)
}
//完成
ceartPregress.prototype.end=function()
{    
    this.oDiv.style.display="block";
    this.oBg.style.display="block";
    var _oDiv=this.oDiv;
    var _oBg=this.oBg;
    var ele=this.oEle;
    var _ccc=getStyle(ele, "left")
    var eft=parseInt(_ccc);
    clearInterval(this.timer1);
    this.timer2=setInterval(function(){
        if(eft<0){
            eft+=1;
            ele.style.left=eft+"px";
        }
        else{
            clearInterval(this);
            _oDiv.style.display="none";
            _oBg.style.display="none";
        }
    },10)
}
//获取对象属性
function getStyle(obj, name)
{
    if(obj.currentStyle)
    {
        return obj.currentStyle[name];
    }
    else
    {
        return getComputedStyle(obj, false)[name];
    }
}