Doesn't work. I think you chose the wrong library. If I switch it from MooTools to jQuery, it does work. But for something simple, no library should be required. Something like:
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<style type="text/css">
#myimage {
visibility: hidden;
display: block;
}
</style>
</head>
<body>
<span id="trigger">Text</span>
<img id="myimage" src="earth.jpg" alt="original image" title="">
<script type="text/javascript">
document.getElementById('trigger').onmouseover = function(){
document.getElementById('myimage').style.visibility = 'visible';
}
document.getElementById('trigger').onmouseout = function(){
document.getElementById('myimage').style.visibility = 'hidden';
};
</script>
</body>
</html>
Demo:
http://home.comcast.net/~jscheuer1/side/tidbits/mouseimage.htm
But one of the two scripts I mentioned here:
http://www.dynamicdrive.com/forums/showthread.php?72654-Mouse-over-text-to-image&p=289597#post289597
might still be a better fit. It all depends upon what they ultimately want to do.
Oh, and Bernie - Thanks for your contribution so far to this thread. But please don't turn this into a discussion about possibilities or comments on my code or your code or my comments on your code. Basically Please wait until the OP responds.