How to validate a form when the submit button is outside of this form, with angularJs?

Problem

I have a form element created with AngularJS with a submit button within it and I would like to put this button outside of this form. How can I do that with Angular and have my form still validated?

e.g main html code:

<div class="sd-chk-steps" ng-show="!step_03" ng-hide="step_03">

<!-- Panel Address -->
<div id="sd-p-chk-1" class="large-8 columns sd-p-chk">
  <div class="cover step_complete" ng-show="step_01" ng-hide="!step_01">
  </div>
  <sd-panel-address >
  <!-- first form -->
  </sd-panel-address>
</div>
<!-- /. Panel Address -->

<!-- Panel delivery -->
<div id="sd-p-chk-2" class="large-8 columns sd-p-chk">
  <div class="cover" ng-show="!step_01" ng-hide="step_01"></div>
  <sd-panel-delivery>
  <!-- second form -->
  </sd-panel-delivery>
  <div class="cover step_complete" ng-show="step_02" ng-hide="!step_02"></div>
</div>
<!-- /. Panel delivery  -->

<!-- Panel payment -->
<div id="sd-p-chk-3" class="large-8 columns sd-p-chk">
  <div class="cover" ng-show="!step_02" ng-hide="step_02"></div>
  <sd-panel-payment>
  <!-- third form -->
  </sd-panel-payment>
</div>
<!-- /. Panel payment -->

<!-- group botton submit -->
<div class="sd-chk-box">
    <div class="sd-chk-box-inner">

        <div class="large-8 columns sd-box-chk-btn sd-chk-btn-sm">
          <button ng-click="clickBtn(shipping.$valid)" type="submit" class="sd-chk-btn sd-button-cta" ng-disabled="shipping.$invalid">
            Next
          </button>
        </div>

        <div class="large-8 columns sd-box-chk-btn sd-chk-btn-sm">
          <button class="sd-chk-btn sd-button-cta" ng-click="clickBtnStep02(formDelivery.$valid)" ng-disabled="formDelivery.$invalid">
            NEXT
          </button>
        </div>

        <div class="large-8 columns sd-box-chk-btn sd-chk-btn-sm">
          <button class="sd-chk-btn sd-button-cta" ng-click="clickBtnStep03(payment.$valid)" ng-disabled="payment.$invalid">
            PLACE ORDER
          </button>
        </div>

    </div>
</div>
<!-- /. group botton submit -->

e.g form html code:

<form id="shipping" class="shipping" name="shipping" 
      novalidate
      ng-submit="form.submit(shipping.$valid)"
      ng-class="{'loading': form.submitting, 'is-el-dirty' : shipping.$dirty || shipping.dirty}">
      <fieldset>
        <div class="row">
          <div class="large-12 columns">
            <label>
              <input type="text" name="name" placeholder="Name" ng-model="form.data.name" required/>
            </label>
            <div class="error" ng-if="shipping.$submitted || shipping.name.$touched" ng-messages="shipping.name.$error">
                <p class="text-msg" ng-message="required">You did not enter your name</p>
            </div>
          </div>
          <div class="large-12 columns">
            <label>
              <input type="text" name="surname" placeholder="Surname" ng-model="form.data.surname" required/>
            </label>
            <div class="error" ng-if="shipping.$submitted || shipping.surname.$touched" ng-messages="shipping.surname.$error">
                <p class="text-msg" ng-message="required">You did not enter your Surname</p>
            </div>
          </div>
        </div>
      </fieldset>
</form>

e.g controller code:

(function() {

  'use strict';

  /**
   * @ngdoc function
   * @name myApp.controller:globalCtrl
   * @description
   * # globalCtrl
   * Controller of the myApp
   */

  var myApp = angular.module('myApp');


  myApp.controller('globalCtrl', function($scope, $locale, $rootScope) {

      // Check if checkbox it's checked
      $scope.checked = true;

      // got to step 2
      $scope.clickBtn = function(form) {
          //valid form
          if (form === true) {
              console.log('Form is valid, $rootScope.step_01= ' + $rootScope.step_01);
              $rootScope.step_01 = true;
              $rootScope.notValidStpe_01 = true;
          }

          //invalid form
          if (form === false) {
              $rootScope.step_01 = false;
              $rootScope.notValidStpe_01 = false;
              console.log('Form is invalid, $rootScope.step_01= ' + $rootScope.step_01);
          }
      };

      // got to step 3
      $scope.clickBtnStep02 = function(form) {
          //valid form
          if (form === true) {
              console.log('Form is valid, $rootScope.step_02 "'+ $rootScope.step_02);
              $rootScope.step_02 = true;
              $rootScope.notValidStpe_02 = true;

          }

          //invalid form
          if (form === false) {
              $rootScope.step_02 = false;
              $rootScope.notValidStpe_02 = false;
              console.log('Form is invalid, $rootScope.step_02= ' + $rootScope.step_02);
          }
      };


      // All steps completed
      $scope.clickBtnStep03 = function(form) {
          //valid form
          if (form === true) {
              console.log('Form is valid, $rootScope.step_03 "'+ $rootScope.step_03);
              $rootScope.step_03 = true;
              $rootScope.notValidStpe_03 = true;

          }

          //invalid form
          if (form === false) {
              $rootScope.step_03 = false;
              $rootScope.notValidStpe_03 = false;
              console.log('Form is invalid, $rootScope.step_03= ' + $rootScope.step_03);
          }
      };

  });

}(window, window.angular));enter code here

e.g app.js code

(function() {

    'use strict';


    var myApp = angular
        .module('myApp', [
            'ngResource',
            'ngAnimate',
            'ngMessages',
            'templates'
        ]);


    myApp.run(function($rootScope) {
        $rootScope.step_01 = false;
        $rootScope.step_02 = false;
        $rootScope.step_03 = false;

        $rootScope.notValidStpe_01 = false;
        $rootScope.notValidStpe_02 = false;
        $rootScope.notValidStpe_03 = false;
    });

}(window, window.angular));
Problem courtesy of: Fanatic

Solution

As I understand You try to do form wizzard. However you don't need multiple form element, Just use one form element at the top. For child form use ng-form directive to valiadate them seperately.

You can find detailed documentation https://docs.angularjs.org/api/ng/directive/ngForm about using ng-form

Something like this

 <form id="complateOrder" name="orderForm" ng-init="showShippingForm = true">

    <div ng-form="" name="shipping" ng-show="showShippingForm">
       shippig fields
    <button type="button" ng-disabled="shipping.$invalid" ng-click="showDeliveryForm=true">Next</button>
    </div>
    <div ng-form="" name="delivery" ng-show="showDeliveryForm && shipping.$valid" ng-hide="shipping.$invalid" >
       delivery fields
       <button type="button" ng-disabled="shipping.$invalid  && delivery.$invalid" ng-click="showPaymentForm=true">Next</button>
    </div>
    <div ng-form="" name="payment" ng-show="showPaymentForm && shipping.$valid && delivery.$valid " ng-hide="shipping.$invalid && delivery.$invalid">
       payment fields
       <button type="submit" ng-disabled="orderForm.$invalid && shipping.$invalid && payment.$invalid && delivery.$invalid">Submit All</button>
    </div>
    <div>
        <button type="button" ng-click="showPaymentForm ? (showPaymentForm = false; showDeliveryForm= true):showDeliveryForm ? (showDeliveryForm=false; showShippingForm = true):showShippingForm = true">Prev</button>
    </div>

 </form>
Solution courtesy of: Mehmet Otkun

Discussion

If the submit button is outside of the form, then you can wrap your button and form with an ngForm (yes, ngForms can be nested). Give your ngForm a name so that you can handle the submit click and reference the form object by name in the same scope context

Discussion courtesy of: pixelbits

The clue is using the ngForm directive and assign a form name attribute which references to the $rootScope.

<form name="$root.myForm" id="form_id">
    <input type="text" name="myField" required>
</form>

<button form="form_id" ng-disabled="$root.myForm.myfield.$invalid">
    Submit
</button>

That works.

Discussion courtesy of: user3435330

Even more concise than this answer:

<form name="myForm">
    <input type="text" name="myField" required>
</form>

<button ng-disabled="myForm.myField.$invalid">
    Submit
</button>

(Note that you don't even need to define myForm in the underlying controller and you can also omit the form attribute.)

Discussion courtesy of: Daniel

This recipe can be found in it's original form on Stack Over Flow.