css3渐变 transition使用方法

<style>
div{
    width:300px;
    height:300px;
    background:#89F;
    margin:100px auto;

    transition:width 1s ease-out .5s;
    -moz-transition:width 1s ease-out .5s;
    -webkit-transition:width 1s ease-out .5s;
    -o-transition:width 1s ease-out .5s;
}
div:hover{
    width:600px;
}
</style>

<div></div>