<div id="box" style="width:100px; height:100px; border:1px solid #000"></div>
<input id="rndc" type="button" value="随机变色"/>
<script>
function rc(){
return parseInt(Math.random()*256);
}
$(function(){
$("#rndc").click(function(){
$("#box").css("background-color","rgb("+rc()+","+rc()+","+rc()+")");
});
});
</script>