title: Angular service function isn't working on user input
body: <p>I'm trying to learn how to make angular services, so I' ve made one but it only works as the page loads and it gives input value instead of function result.</p>
  
  <p>HTML: </p>
  
  <pre><code>&lt;input type="text" ng-model="hexVal"&gt;
  &lt;p&gt;Hex service: {{hex(hexVal)}}&lt;/p&gt;
  </code></pre>
  
  <p>JS: </p>
  
  <p>Service itself:</p>
  
  <pre><code>app.service('hexafy', function() {
      this.myFunc = function (x) {
          return x.toString(16);
      };
  });
  </code></pre>
  
  <p>Usage of service:</p>
  
  <pre><code>$scope.hexVal = 255;
  $scope.hex = function(arg){
      return hexafy.myFunc(arg);
  };
  </code></pre>