<div id="sign">this is test!</div>

<style type="text/css">.out{background-color: gray;}.over{background-color: red;}.down{background-color: yellow; }</style>

$(function(){var sign=document.getElementById("sign");changBkColor(sign);});function changBkColor(obj){obj.onmouseover=function(){ this.className="over"; };//鼠標懸停事件obj.onmouseout=function(){ this.className="out"; };//鼠標離開事件obj.onmousedown=function(){this.className="down";};//鼠標點擊時觸發事件}

/* $(obj).hover(inFunction,outFunction)*　等同于$(obj).mouseover().mouseout();*/$(function(){$('#sign').hover(function() {$('#sign').addClass('over');}, function() {$('#sign').removeClass('over').addClass('out');});});