angularjs update value of ng-model to set default value
<p>I am trying to set default value of <strong>username</strong>( $scope.userName) and <strong>password</strong>( $scope.password),I have tried with ng-init but its not working,  but its not working here is my code : </p>

<pre><code>APP.directive('loginUser', ['$http','$interval','$rootScope','$timeout', function ($http,$interval,$rootScope,$timeout) {
function link($scope, element, attrs) {

    $scope.userName = 'Ali';
    $scope.password = 'pass';

}

return {
    link: link
};


}]);
</code></pre>

<p><strong>here is my html</strong> </p>

<pre><code>&lt;div class="modal-body" login-user  &gt;

    &lt;form class="custom-form" name="loginForm" ng-submit="loginSubmit()" novalidate&gt;

        &lt;label class="museo_sans500" for="email"&gt;Nome utente o indirizzo email&lt;/label&gt;
        &lt;input type="text" class="form-control museo_sans300" id="userName" placeholder="Nome utente o indirizzo email" ng-init="userName='&lt;?php echo "Yesss" ?&gt;'"   name="UserName" minlength="5" ng-model="userName" required="required"&gt;

      &lt;div class="form-group"&gt;
        &lt;label class="museo_sans500" for="password"&gt;Password&lt;/label&gt;
        &lt;input type="password" class="form-control museo_sans300" id="password" placeholder="Password" name="password"  minlength="5" ng-model="password"  required="required"&gt;
      &lt;/div&gt;
      &lt;div class="form-group"&gt;
        &lt;label class="museo_sans700"&gt;&lt;a href="javascript:void(0)"  ng-click="forgotPasswordShow()"&gt;Hai dimenticato la password?&lt;/a&gt;&lt;/label&gt;
        &lt;label class="museo_sans700" style="margin-left: 30px;"&gt;&lt;input type="checkbox" ng-model="rememberMe" name="remember-me"&gt; Ricordami&lt;/label&gt;
      &lt;/div&gt;
      &lt;button type="submit" class="btn play-now museo_sans500 m-t-20px login-btn"  ng-disabled="loginForm.$invalid"&gt;ENTRA&lt;/button&gt;
      &lt;div class="or museo_sans500"&gt;oppure&lt;/div&gt;

    &lt;/form&gt;
  &lt;/div&gt;
</code></pre>

<p>Thanks in advance</p>