<div id="show5" style="position: absolute; width: 464; height: 197; z-index: 4; left: 291; top: 101">...</div>
<a href="javascript:alert(show5.offsetWidth);">aaaaaaaaa</a>
<a href="javascript:alert(show5.offsetWidth);">aaaaaaaaa</a>
加边线的高宽 offsetHeight clientWidth