title: .css() is not a function [jQuery]?
body: <p>I have the following custom tag/directive :</p>
  
  <pre><code>&lt;tile class="ng-scope gridster-item" tilevalue="1" gridster-item="tile" row="0" col = "0" ng-repeat="tile in selectedTiles"&gt; &lt;/tile&gt;
  </code></pre>
  
  <p>I've created a keyboard control where the goal is to focus on each tile ("tile" directive) in the <code>selectedTiles array</code> per keyboard event <code>(shift + right arrow)</code>.</p>
  
  <pre><code>// Keyboard Tile Navigation
  
          //Starting pos
          var curIndex = -1
  
          //keyboard control
          $(document).keydown(function(event) {
  
          if (event.shiftKey &amp;&amp; event.which === 39) {
                  console.log("right");
                  focusNext();
                  }
             });
  
          function focusNext() {
              focusTile(+1);
          }
  
          function focusTile(delta) {
  
              var visibleTiles = $scope.selectedTiles;
              var elem = $("[gridster-item='tile']");
  
              curIndex = curIndex + delta;
              el = elem[curIndex];
  
          el.attr('tabindex', -1).focus();    
          el.css("border-color", "yellow");
  
          }
  </code></pre>
  
  <p>When I get a console log of the variable <code>elem</code> I get the array of tiles that appear in the dom (as is expected). The problem is when I try to add a <code>.attr()</code> function or a <code>.css()</code> function, I get the error stating these are not functions, how can i adjust?</p>