js 类的this 代表的含义（张艳冲的博客）

<SCRIPT LANGUAGE="JavaScript">
<!--
function CScreen(id)
{
        this.pos=0;
        this.o=document.getElementByIdx_x_x(id);
        this.txt=this.o.innerText;
        var self=this;
        this.init=function(){    // 为什么这个用self 呢 因为每一个function 相当于一类 要是写this 就是本身了 所以写self  指的是上面的类 而不是本身的类
                setInterval(function(){self.knock();},300);
        }
        this.knock=function(){                
                if(this.pos>this.txt.length)
                        this.pos=0;
                this.curTxt=this.txt.substr(0,this.pos);
                this.o.innerText=this.curTxt + "_";
                this.pos++;
                setTimeout(function(){self.flashCursor();},150);
        }
        this.flashCursor=function()
        {
                this.o.innerText=this.curTxt;
        }
}

window.onload=function (){
        new CScreen("screen").init();
};
//-->
</script>
<div id="screen" style="width:300px;height:25px;background-color:#000000; color:#FFFFFF; font-size:14px; padding:2px;text-align:left">JS文字特效之打印文字效果</div>