CSS3过渡效果 兼容IE6、IE7、IE8

<style>
.box{
width:120px;height:40px;background:yellowgreen;line-height:40px;transition:width 1s;cursor:pointer;
}
.box:hover{
width:180px;
}
</style>

<div class="box">Hello World</div>

<!--[if lte IE 8]>
<style>
.box:hover{
width:100px\9;
}
</style>
<script>
$(function(){
$(".box").hover(function(){
$(this).animate({width:180},500)
},function(){
$(this).animate({width:120},500)
});
});
</script>
<![endif]-->