$("#show").click(function(){
alert($("#div1").innerHeight());
//$("#div1").height("120px");
});
$("p#p1").hide();
<script src="http://cdn.static.runoob.com/libs/jquery/1.10.2/jquery.min.js">
</script>
<div id="div1">13</div>
<h1>Property,Attribute</h1>
<p id="p1">Paragraph1</p>
<p id="p2">Paragraph2</p>
<button id="show">显示</button>
<button id="hide">隐藏</button>
#div1{
height:30px;
border:5px solid;
}