交换图像效果的实现

 1 <script language="javascript">
 2 function changeImg(obImg,sNewURL)
 3 {
 4      if(sNewURL!="") obImg.src=sNewURL;
 5 }
 6 
 7 function preLoad(sURL)
 8 {
 9      if(sURL!="")
10      {
11           var obImg=new Image();
12           obImg.src=sURL;
13      }
14 }
15 preLoad("images/image1.jpg");
16 preLoad("images/image2.jpg");
17 </script>
18 <img src="images/image1.jpg" border="0" width="478" height="200" onmouseover="changeImg(this,'images/image2.jpg');" onmouseout="changeImg(this,'images/image1.jpg');">