show hide text box

Hi

Im looking for a way to show hide text box on select option change



<select name="letter_type" id="lt">
<option value="Registered">Registered</option>
<option selected="selected" value="Unregistered">Unregistered</option></select>
<input name="textfield7" id="regty" type="text" accesskey="1" tabindex="1" size="20" />


i wana show that text box if user select "Registered" from select option.

any help would be great



sorry for language errors.

Thanks

Here you are:-

<select name="letter_type" id="lt" onchange = "show()">
<option value="Registered">Registered</option>
<option selected="selected" value="Unregistered">Unregistered</option>
</select>
<br><br>
<div id = "mydiv" style="display:none">
<input name="textfield7" id="regty" type="text" accesskey="1" tabindex="1" size="20" />
</div>

<script type = "text/javascript">

function show() {
var val = document.getElementById("lt").value;
if (val == "Registered") {
document.getElementById("mydiv").style.display="block";
}
else {
document.getElementById("mydiv").style.display="none";
}
}

</script>

Quizmaster: Which animal do we get vension from?
Contestant: Snakes.

Thanks a lot

Thanks a lot

WWhhaatt ddooeess dduupplleexx mmeeaann?? :D:D