well, u need to use layers in that case, the coding might be really huge, i can just give u an idea:
<div style="position:absolute;left10px;top:15px;visibility:hidden" id='DivTg'></div>
<select ..... onclick="ShowToolTip(this.value)">
<script>
function ShowToolTip(TheValue)
{
document.getElementById('DivTg').innerText=TheValue
document.getElementById('DivTg').style.visibility="visible"
}
</script>
Known is handfull, Unknown is worldfull