JavaScript 控制图片改变重叠顺序的代码(鼠标移动切换)

<html> <head> <title>改变图片重叠顺序</title> <style type="text/css"> .s1{position:absolute; top:10;left:10; } .s2{position:absolute; top:50;left:50; } </style> <script language="javascript"> <!-- function ch(obj){ ID1.style.zIndex = 0; ID2.style.zIndex = 0; obj.style.zIndex = 1; } //--> </script> </head> <body> <img src="http://img.gxlcms.com//Uploads-s/new/2019-09-17-201917/20101031232216942.jpg" id="ID1" class="s1" onMouseOver="ch(this)"> <img src="http://img.gxlcms.com//Uploads-s/new/2019-09-17-201917/20101031232216617.jpg" id="ID2" class="s2" onMouseOver="ch(this)"> </body> </html>
[Ctrl+A 全选 注:如需引入外部Js需刷新才能执行]