Disable drop down box on radio button click

Question

I have two radio buttons and a drop down box as you can see below. What I want to do is: 1. While no is checked, either hide, or grey out the drop down box, and 2. While yes is checked, show the drop down box.

Any pointers would be appreciated!

<td colspan="4">
<input name="discount" type="radio" id="Yes" value="Yes" />Yes
<input name="discount" type="radio" id="No" value="No" checked="checked" />No<br />  
<select class="purple" name="discountselection" id="discountselection">
<option value="1 Year" selected="selected">1 Year</option>
<option value="2 Years">2 Years</option>
<option value="3 Years">3 Years</option>
</select>                  
</td>

Answer 1

   <script type="text/javascript">
                   $("#Yes").click(function() {
                        $("#discountselection").attr("disabled", false);
                        //$("#discountselection").show(); //To Show the dropdown
                    });
                    $("#No").click(function() {
                        $("#discountselection").attr("disabled", true);
                        //$("#discountselection").hide();//To hide the dropdown
                    });
    </script>

Also, set the dropdown's display style, or disabled property in HTML based on your default radiobutton selected on page load.

 <select  name="discountselection" id="discountselection" disabled="disabled">
    <option value="1 Year" selected="selected">1 Year</option>
    <option value="2 Years">2 Years</option>
    <option value="3 Years">3 Years</option>
    </select>

Answer 2

$('input:radio[name="discount"]').change(function() {
    if ($(this).val()=='Yes') {
        $('#discountselection').attr('disabled',true);
    } else
        $('#discountselection').removeAttr('disabled');
});​

http://jsfiddle.net/uSmVD/