window.onload=function(){??? var aA=document.getElementsByTagName('a');?? ?for(var i=0; i<aA.length; i++){?? ??? ?aA[i].onmouseover=function(){?? ??? ??? ?var This=this;?? ??? ??? ??? ??? ??? ?This.time=setInterval(function(){?? ??? ??? ??? ??? ?This.style.width=This.offsetWidth+8+"px";?? ??? ??? ??? ??? ?if(This.offsetWidth>=160)?? ??? ??? ??? ??? ?clearInterval(This.time);?? ??? ??? ??? ?},30)?? ??? ?}這段代碼中的this具體是指什么？是aA[i].style.width嗎？為什么我將this用aA[i].style.width取代后代碼不運行？正確寫法是什么？