获取当前样式并改变div样式

<script>

function getStyle(obj,attr){

return obj.currentStyle?obj.currentStyle[attr]:getComputedStyle(obj,null)[attr];

}

function t(){

var div=document.getElementsByTagName('div')[0];

if(div.className.indexOf("")>=0){

div.className="test2";

}else{

div.className="test1";

}

div.style.width=parseInt(getStyle(div,"width"))+5+'px';

}

</script>