javascript - How to call custom directive on form submit -

i have custom directive works when once change input value when submit form without changing input field value directive not display error message.

html code:

    <form name="myform" role="form" class="form-horizontal" method="post" novalidate>         <div class="form-group">             <label class="control-label col-sm-3" for="firstname">first name :</label>             <div class="col-sm-9">              <input name='firstname' class="form-control" type='text' required ng-model='name' string> </div>         </div>  <div class="form-group">              <input type="submit" value="submit" class="btn btn-success" />         </div>      </form> 

directive :

 validationmodule.directive('string', function () {     return {         restrict: 'a',         require: 'ngmodel',          link: function (scope, element, attr, ctrl) {             function validationerror(value) {                  if (value.length < 1) {                     ctrl.$setvalidity('required', false);                     //showpopover(element, "required field");                     errorvalidation(element, "required field");                //     $(element).popover('show');                 }                 if (/[a-za-z]/.test(value)) {                     ctrl.$setvalidity('invalid', true);                     // $(element).popover('destroy');                     successvalidation(element);                 }                 if (/[0-9]/.test(value)) {                     ctrl.$setvalidity('invalid', false)                     errorvalidation(element, "number not allowed");                     // showpopover(element, "number not allowed");                  //   $(element).popover('show');                 }                  return value;             }             ctrl.$parsers.push(validationerror);         }     }; }); 

how can call directive perform validation on submit event ?

i don't know version of angular using, since 1.3 validators not hacked parsers. see $validators in https://docs.angularjs.org/api/ng/type/ngmodel.ngmodelcontroller using such generic names directives discouraged due possible name collisions. use prefix eg mystring