Enable disable bootstrap dropdown using jquery

if (self.hasClass('byBlackRadio')) {

        $('.byDateText').attr("disabled", "disabled");

        $('.selectBasic').attr("disabled", "disabled");

    } else if (self.hasClass('byResRadio')) {

        $('.byDateText').removeAttr("disabled");

        $('.selectBasic').removeAttr("disabled");

      }

    }

  Here byBalckRadio and byResRadio both are RadioButton having classes on click on this code ifired. but when i need that when form is loaded then selectBasic and byDateTest should be disabled after disabling removeattr is not working of .selectBasic