jQuery增加千分符

<dl>   <dt nc_type="no_spec">      <span class="red">*</span>成本价：   </dt>   <dd nc_type="no_spec">      <input type="text" class="text decimal" name="storeGoods.cost" dataType="double" id="cost"         isrequired="true" />   </dd>
</dl>
<script>   $(".decimal").on("blur",function(money){      var discount = $(this).val();      var total;      if(discount!==''&&!isNaN(discount)){         total = parseFloat(discount);         total = total.toFixed(2) + "";         var re=/(\d{1,3})(?=(\d{3})+(?:$|\.))/g;         var n=total.replace(re,"$1,");         return  $(this).val(n);      }    });</script>