<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script src="http://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js" type="text/javascript" charset="utf-8"></script>
<style type="text/css">
div{
width: 200px;height: 200px;background: red;
}
</style>
</head>
<body>
<div id=""></div>
</body>
</html>
<script type="text/javascript">
$('div').on('click',function(){
// $(this).css('background','blueviolet')
// $(this)[0].style.background = 'yellow'
$(this).get(0).style.background = 'yellow'
}).on('mouseenter',function(){
alert(555)
}).on('mouseleave',function(){
alert(888)
})
$('div').off('mouseenter')
</script>