ПРИМЕР

Код:
<script language="JavaScript"> 
if (document.images) { 
img1on = new Image(); 
img1on.src ="http://partnery.clan.su/GIF/Vkontakte.gif"; 
img1off = new Image(); 
img1off.src = "http://partnery.clan.su/GIF/konkyrs.gif"; 
} 
function imgOn(imgName) { 
if (document.images) { 
document[imgName].src = eval(imgName + "on.src"); }}//osw 
function imgOff(imgName) { 
if (document.images) { 
document[imgName].src = eval(imgName + "off.src"); }} 
</script> 
<a href="" onmouseover="imgOn('img1')" ;="" onmouseout="imgOff('img1')"> 
<img src="http://partnery.clan.su/GIF/Vkontakte.gif" border="0" name="img1"></a>