问如何使用jQuery/JavaScript来找出单选按钮何时不被选中？

EN

<!-- html on one of the pages -->
<fieldset>
  <label for="viaMail">Send offers to my mail</label>
  <input type="checkbox" id="viaMail" class="slide" autocomplete="off">

  <label for="viaEmail">Send offers to my email address</label>
  <input type="checkbox" id="viaEmail" autocomplete="off">

</fieldset>

<div class="viaMail">  <!-- div hidden with css using display: none rule -->
   <!-- input fields for mailing addresses etc --> 
</div>
<!-- end page one html -->

<!-- html on page two -->   
<fieldset>
  <label for="viaMail">Send offers to my mail</label>
  <input type="radio" name="group1" id="viaMail" class="slide" autocomplete="off">

  <label for="viaEmail">Send offers to my email address</label>
  <input type="radio" name="group1" id="viaEmail" autocomplete="off">

</fieldset>

<div class="viaMail">  <!-- div hidden with css using display: none rule -->
   <!-- input fields for mailing addresses etc -->
</div>

/* the js function */

ShowHideDiv={
init:function(){
    var radcheck = $(".slide");

//if the input element has the class 'slide' then the value of it's 'id' attribute 
//is retrieved and the class which has the same name as the 'id' of the current input
//element is hidden or slided into view - in this case the 'viaMail' class

    radcheck.on("change",function(){
        if($(this).prop('checked')== true) {
            $('body').find("."+$(this).attr('id')).slideDown('slow');
        }
        else {
            $('body').find("."+$(this).attr('id')).slideUp('fast');
        }
    });

}
  }