Sometimes it is useful to hide some input boxes when they are not needed. This simple script hides unnecessary inputs and shows the ones that are needed.

function selectChanged(sel)
{
if(sel.selectedIndex==0)
{
document.getElementById('input-id-1').style.display='';
document.getElementById('input-id-2').style.display='none';
}
else
{
document.getElementById('input-id-1').style.display='none';
document.getElementById('input-id-2').style.display='';
}
}
Here is the full HTML page for testing purposes. You will need to modify it to your needs:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<script type="text/javascript">
function selectChanged(sel)
{
if(sel.selectedIndex==0)
{
document.getElementById('input-id-1').style.display='';
document.getElementById('input-id-2').style.display='none';
}
else
{
document.getElementById('input-id-1').style.display='none';
document.getElementById('input-id-2').style.display='';
}
}
</script>
</head>
<body>
<form action="" method="post">
<table>
<tr><td>Input-1</td><td><input name="input-1" type="text" /></td></tr>
<tr><td>Input-2</td><td><input name="input-2" type="text" /></td></tr>
<tr><td>Input Select</td><td><select name="select-name" onchange="selectChanged(this)"><option>Option 1</option><option>Option 2</option></select></td></tr>
<tr id="input-id-1"><td>Input-3</td><td><input name="input-3" type="text" value="One" /></td></tr>
<tr id="input-id-2" style="display:none"><td>Input-4</td><td><input name="input-4" type="text" value="Two" /></td></tr>
<tr><td colspan="2" align="right"><input name="submit" type="submit" value="Submit" /></td></tr>
</table>
</form>
</body>
</html>
Thank You! This is just what I needed.