text: (function(){
  
    function checkdate(day, month, year){
      var date = new Date(year + "-" + month + "-" + day);
  
      if(date.getDate() == day && (date.getMonth() + 1) == month && date.getFullYear() == year){
        return true;
      }else {
        return false;
      }
    };
    $(document).ready(function(){
      $("#signup-form").submit(function(){
        var day = $("#b_day").val();
        var month = $("#b_month").val();
        var year = $("#b_year").val();
  
        if(!checkdate(day, month, year)){
          $("#b_error").html("Ngay thang khong hop le");
          return false;
        }else {
          return true;
        }
      });
    });
  })();
  