title: Validation not triggered when data binding a number input's min / max attributes
body: <p>I have numerous number input fields that have min and max attribute values that depend on logic elsewhere in my AngularJS app, but when using data bindings within these attributes they are no longer validated by Angular, however, the HTML 5 validation still appears to pick them up.</p>
  
  <pre class="lang-js prettyprint-override"><code>var myApp = angular.module('myApp', []);
  function FirstCtrl($scope) {
      $scope.min = 10;
      $scope.max = 20;
  }
  </code></pre>
  
  <pre class="lang-html prettyprint-override"><code>&lt;div ng-app="myApp"&gt;
      &lt;div ng-controller="FirstCtrl"&gt;
          &lt;form name="myForm"&gt;
              &lt;input type="number" name="one" required="required"
                     min="10" max="20" ng-model="one" /&gt;
              &lt;input type="number" name="two" required="required"
                     min="{{ min }}" max="{{ max }}" ng-model="two" /&gt;
              &lt;button ng-disabled="!myForm.$valid"&gt;Submit&lt;/button&gt;
          &lt;/form&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>Live version: <a href="http://jsfiddle.net/kriswillis/bPUVH/2/" rel="noreferrer">http://jsfiddle.net/kriswillis/bPUVH/2/</a></p>
  
  <p>As you can see, the validation is still handled fine in the HTML/CSS (Bootstrap) as both fields turn red when invalid, however, the submit button (handled by Angular) is not disabled when the second field is invalid. Also, there are no min and max properties in <code>myForm.two.$error</code> as there are in <code>myForm.one.$error</code>.</p>
  
  <p>Can anyone see where I'm going wrong?</p>