title: Angular IE8 attrs.$set / element.attr don't work
body: <p>I transform my own tag into input.
  I can choose readonly / disable for input using select.
  I did it. It works. But not in ie8 )).</p>
  
  <p>I read official docs for Angular and IE8.
  I added it. But my app doesn't work in ie8.</p>
  
  <p>I can't add readonly / disabled attributes (readonly="readonly" and disabled="disabled")</p>
  
  <p><a href="http://plnkr.co/edit/TSQLb3nmdq3emqcUMTzx?p=preview" rel="nofollow">plunker</a></p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html xmlns:ng="angularjs.org" id="ng-app" ng-app="dir"&gt;
  &lt;head&gt;
  &lt;!--[if lt IE 8]&gt;
  
      &lt;script src="html5shiv.js"&gt;&lt;/script&gt;
  &lt;![endif]--&gt;
  
  &lt;!-- Internet Explorer AngularJS element creation --&gt;
  &lt;!--[if lte IE 8]&gt;
      &lt;script&gt;
          document.createElement('dhtmlxdate');
      &lt;/script&gt;
      &lt;script src="http://cdnjs.cloudfare.com/ajax/libs/json3/3.2.4/json3.min.js"&gt;&lt;/script&gt;
  &lt;![endif]--&gt;
      &lt;meta charset="utf-8" /&gt;
      &lt;title&gt;ie8&lt;/title&gt;
  
  &lt;/head&gt;
  &lt;body&gt;
  
  &lt;tag mode="{{mode}}"&gt;&lt;/tag&gt;
  
  &lt;select ng-model="mode"&gt;
      &lt;option&gt;disabled&lt;/option&gt;
      &lt;option&gt;readonly&lt;/option&gt;
  &lt;/select&gt;
  
  
  &lt;script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.1.3/angular.min.js"&gt;&lt;/script&gt;
  &lt;script&gt;
  var myapp = angular.module("dir", []);
      myapp.directive('tag', function(){
      return {
        restrict: 'E',
        replace: true,
        transclude: true,
        scope: false,
        template: '&lt;input type="text" /&gt;'
          ,
  
          link: function(scope, element, attrs) {
  
              attrs.$observe('mode', function(value) {
                  switch(value) {
                      case "disabled":
                          //attrs.$set('disabled', 'disabled');
                          element.attr('disabled', 'disabled');
                          element.removeAttr('readonly');
                          break;
                      case "readonly":
                          //attrs.$set('readonly', 'readonly');
                          element.attr('readonly', 'readonly');
                          element.removeAttr('disabled');
                          break;
                  }
              });
  
          }
              };
          }); 
  
      &lt;/script&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>