<script>
function seetext(x){
x.type = "text";
}
function seeasterisk(x){
x.type = "password";
}
</script>
<body>
<img onmouseover="seetext(a)" onmouseout="seeasterisk(a)" border="0" src="smiley.gif" alt="Smiley" width="32" height="32">
<input id = "a" type = "password"/>
</body>
Try this see if it works