Email Validation Client Script ServiceNow

function onChange(control, oldValue, newValue, isLoading) {
    if (isLoading || newValue == '') {
          return;
    }
  g_form.hideErrorBox('user_email');
       var pattern =/^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;   // regex pattern
   if(!pattern.test(newValue)){
     g_form.showErrorBox('user_email', getMessage('Invalid Email Address'));//show error messege
           g_form.setValue('user_email', '');
   }
}