abstract：<!DOCTYPE html><html><head><meta charset="UTF-8"><title>Document</title><script type="text/javascript" src="js/jquery-3.3.1.min.js"
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Document</title>
<script type="text/javascript" src="js/jquery-3.3.1.min.js"></script>
<style type="text/css">
.box{
width: 300px;
height: 300px;
background: pink;
border-radius: 300px;
text-align: center;
line-height: 300px;
}
</style>
<script type="text/javascript">
$(document).ready(function(){
$(document).mouseover(function (aa){
$('span').text('坐标：'+aa.pageX+','+aa.pageY);
})
$('button').click(function(){
$('div').addClass('box');
$('div').mouseover(function(){
$(this).css('background','red');
$(this).html("<h2>添加h2标签</h2>")
$('div h2').css({'color' :'orange','font-size': '38px'});
})
})
})
</script>
</head>
<body>
<span></span>
<div></div>
<button>点击</button>
</body>
</html>
获取元素，然后.上事件名称，要执行的事件函数代码块！