<script type="text/javascript"> 
 if (document.images) 
 { 
 image1 = new Image; 
 image2 = new Image; 
 image1.src = "http://ra.foto.radikal.ru/0709/2f/8a82c39bbb8f.jpg"; 
 image2.src = "http://i050.radikal.ru/0810/39/0bd7d36ee55b.jpg"; 
 } 
 function chgImg(name, image) 
 { 
 if (document.images) 
 { 
 document[name].src = eval(image+".src"); 
 } 
 } 
 </script> 
 ... 
 <a href="/" onMouseOver='chgImg("enter", "image2")' 
 onMouseOut='chgImg("enter", "image1")'><img name="enter" 
 src="enter1.gif" border="0" alt="Входите, если рискнете!"></a>