title: Enable a button on entering text in input field
body: <p>I want to enable a button only when a text is entered on an input field. So far I have this code on my app.js</p>
  
  <pre><code>.controller("EnableDisable", function(){
    $scope.editableInput = false;
  })
  
  .directive("inputDisabled", function(){
    return function(scope, element, attrs){
      scope.$watch(attrs.inputDisabled, function(val){
        if(val)
          element.removeAttr("disabled");
        else
          element.attr("disabled", "disabled");
      });
    }
  });
  </code></pre>
  
  <p>This is the view implementation :</p>
  
  <pre><code>&lt;div ng-controller="EnableDisable"&gt;
  &lt;input type="text" input-disabled="editableInput" /&gt;
  &lt;button ng-click="editableInput = !editableInput"&gt;enable/disable&lt;/button&gt;
        &lt;/div&gt;
  </code></pre>
  
  <p>This is the plunk url:
  <a href="https://plnkr.co/edit/bHtZJ1H5JvM2XTuhft6J?p=preview" rel="nofollow">https://plnkr.co/edit/bHtZJ1H5JvM2XTuhft6J?p=preview</a>
  Presently when I launch the app, the button is not disabled by default.
  Please with the above challenge how can I make the button clickable (receive events)when a text is entered on the input field.
  Kindly assist!</p>