title: require confirmation before updating ng-model or executing ng-change in angularjs checkbox input
body: <p>I have a checkbox input that when checked sets <code>customer.isCompleted</code> to true or false and saves the customer data through a <code>firebase api</code> using <code>ng-change</code></p>
  
  <pre><code>input type="checkbox" ng-model="customer.isCompleted" ng-change="sc.data.$save(customer)"
  </code></pre>
  
  <p>however i want to make sure when customer checks the box, it prompts for confirmation. If users hits OK then, it should check the box, update the <code>ngMode</code>l and fire <code>ngChange</code>otherwise do nothing.(and do this when the box is checked or unchecked). when checked the confirmation box should say message1 and when unchecked it should say message2. </p>
  
  <p>how can I implement this. I'm assuming a directive, but don't know how i'd implement it.</p>