<html>
<script type="text/javascript">
function change()
{
x=document.all.DropDownList1.value;
if(x=="x4")
eval("document.all.Text1.style.visibility='hidden';");
else
eval("document.all.Text1.style.visibility='visible';");
}
</script>
<body>
<form name="form1" method="post" id="form1">
<select name="DropDownList1" id="DropDownList1" onchange="change()">
<option value="x1">x1</option>
<option value="x2">x2</option>
<option value="x3">x3</option>
<option value="x4">x4</option>
</select>
<input id="Text1" type="text" value="cctv"/>
</form1>
</body>
</html>
<script type="text/javascript">
function change()
{
x=document.all.DropDownList1.value;
if(x=="x4")
eval("document.all.Text1.style.visibility='hidden';");
else
eval("document.all.Text1.style.visibility='visible';");
}
</script>
<body>
<form name="form1" method="post" id="form1">
<select name="DropDownList1" id="DropDownList1" onchange="change()">
<option value="x1">x1</option>
<option value="x2">x2</option>
<option value="x3">x3</option>
<option value="x4">x4</option>
</select>
<input id="Text1" type="text" value="cctv"/>
</form1>
</body>
</html>