<html>
<head>
<script>
function ChangeOpacity(x)
{
// Return the text of the selected option
var opacity=x.options[x.selectedIndex].text;
var el=document.getElementById("p1");
if (el.style.opacity!==undefined)
{el.style.opacity=opacity;}
else
{alert("Your browser doesn't support this example!");}
}
</script>
</head>
<body>
<p id="p1">Select a value from the list below, to change this element's opacity!</p>
<select onchange="ChangeOpacity(this);" size="5">
<option></option>0
<option></option>0.2
<option></option>0.5
<option></option>0.8
<option selected></option>1
</select>
</body>
</html>