[jquery] How to show/hide an element on checkbox checked/unchecked states using jQuery?

I have this code:

   <fieldset class="question">
       <label for="coupon_question">Do you have a coupon?</label>
       <input class="coupon_question" type="checkbox" name="coupon_question" value="1" />
       <span class="item-text">Yes</span>
   </fieldset>

   <fieldset class="answer">
       <label for="coupon_field">Your coupon:</label>
       <input type="text" name="coupon_field" id="coupon_field"/>
   </fieldset>

And I would like to show/hide the "answer" fieldset (default is hidden) after a click on the checkbox in fieldset "question" How to do that. I wasn't able to do that using the technique for a classic elemetn like:

<script>
    $().ready(function(){

        $('.question').live('click',function() {
                 $('.answer').show(300);
            }
            ,
            function(){
                $('.answer').hide(200);
            }
        );

    });
</script>

Could somebody help me how to do that using checkbox? Also if possible to null (uncheck) the checkbox when it's hidden.

Try this

<script>
    $().ready(function(){
        $('.coupon_question').live('click',function() 
        {
            if ($('.coupon_question').is(':checked')) {
                $(".answer").show();
            } else {
                $(".answer").hide();
            } 
        });
    });
</script>

Try this

$(".answer").hide();
$(".coupon_question").click(function() {
    if($(this).is(":checked")) {
        $(".answer").show(300);
    } else {
        $(".answer").hide(200);
    }
});

FIDDLE

Simplest - and I changed the checkbox class to ID as well:

$(function() {_x000D_
  $("#coupon_question").on("click",function() {_x000D_
    $(".answer").toggle(this.checked);_x000D_
  });_x000D_
});

.answer { display:none }

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>_x000D_
<fieldset class="question">_x000D_
  <label for="coupon_question">Do you have a coupon?</label>_x000D_
  <input id="coupon_question" type="checkbox" name="coupon_question" value="1" />_x000D_
  <span class="item-text">Yes</span>_x000D_
</fieldset>_x000D_
_x000D_
<fieldset class="answer">_x000D_
  <label for="coupon_field">Your coupon:</label>_x000D_
  <input type="text" name="coupon_field" id="coupon_field" />_x000D_
</fieldset>

$(document).ready(function() {
    $(document).on("click", ".question", function(e) {
       var checked = $(this).find("input:checkbox").is(":checked");
       if (checked) {
           $('.answer').show(300);
       } else {
           $('.answer').hide(300);
       }
    });
});

Try

$(document).ready(function(){
    //Register click events to all checkboxes inside question element
    $(document).on('click', '.question input:checkbox', function() {
        //Find the next answer element to the question and based on the checked status call either show or hide method
        $(this).closest('.question').next('.answer')[this.checked? 'show' : 'hide']()
    });

});

Demo: Fiddle

Or

$(document).ready(function(){
    //Register click events to all checkboxes inside question element
    $(document).on('click', '.question input:checkbox', function() {
        //Find the next answer element to the question and based on the checked status call either show or hide method
        var answer = $(this).closest('.question').next('.answer');

        if(this.checked){
            answer.show(300);
        } else {
            answer.hide(300);
        }
    });

});

    <label  onclick="chkBulk();">
    <div class="icheckbox_flat-green" style="position: relative;">
      <asp:CheckBox ID="chkBulkAssign" runat="server" class="flat" 
       Style="position: 
         absolute; opacity: 0;" />
      </div>
      Bulk Assign
     </label>



    function chkBulk() {
    if ($('[id$=chkBulkAssign]')[0].checked) {
    $('div .icheckbox_flat-green').addClass('checked');
    $("[id$=btneNoteBulkExcelUpload]").show();           
    }
   else {
   $('div .icheckbox_flat-green').removeClass('checked');
   $("[id$=btneNoteBulkExcelUpload]").hide();
   }