window.onload=function(){

var div =document.getElementById('div1');

var cssnew=document.styleSheets[0].cssRules || document.styleSheets[0].rules || window.CSSRule.STYLE_RULE;

var t =null;

function time(speed,target){

clearInterval(t);

t=setInterval(function(){

if(div.offsetLeft==target){

clearInterval(t);

}else{

cssnew[1].style.left=div.offsetLeft+speed+'px';

}

},30)

//cssnew[1].style.width=30+"px";

}

div.onmouseover =function(){

time(10,0)

};

div.onmouseout=function(){

time(-10,-200)

};

}

 ie7 和火狐不会报错 360浏览器回报：Cannot read property 'style' of undefined 请问有什么解决的办法