show and hide div tag based on checkbox selection using javascript

1<input class="coupon_question" type="checkbox" name="coupon_question" value="1" onchange="valueChanged()"/>
2
3<script type="text/javascript">
4    function valueChanged()
5    {
6        if($('.coupon_question').is(":checked"))   
7            $(".answer").show();
8        else
9            $(".answer").hide();
10    }
11</script>
12