title: Extjs - Combobox with data from php file not working
body: <p>I have a combobox and i want to get data from php server
  <br>Here is my Index.html code <b><a href="http://jsfiddle.net/UQcgA/" rel="nofollow">http://jsfiddle.net/UQcgA/</a></b></p>
  
  <p>Here is my data.php file. 
  <br> But when i click to combo then nothing show :(. How can i fix that thanks</p>
  
  <pre><code>&lt;?php
  // function to create json
  function GetCategories() {
      $categories = "{'rows':[";
      $categories = "{'id':'1', 'name':'Category 1'},";
      $categories .= "{'id':'2', 'name':'Category 2'},";
      $categories .= "{'id':'3', 'name':'Category 3'}";
      $categories .= "]}";
      return $categories;
  }
  echo GetCategories(); // sent to client
  ?&gt;
  </code></pre>