title: ajax fails in chrome extension when deployed in a google product like docs or gmail
body: <p>Hi there fellow exchangers!</p>
  
  <p>I am creating a chrome extension that appears above the website a user is viewing.  I want to pull and send data to a database located on a server.  I know that I'll be using xhr and while this works across the web...it oddly fails when I try and deploy this code on sites that are google products, such as gmail and google docs.  It almost seems like google prevents XMLHttpRequest around their sites/products. Ironically enough, those are the two sites that I care the most that this works on.  Any insight on why CORS behaves differently on the <em>.google.com/</em> domain or what I'm missing would be greatly appreciated it.    </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>$.ajax({
      url: urlpath + "db.php?type=symbol&amp;value=",
      type: 'GET',
      data: "{}",
      contentType: "application/json; charset=utf-8",
      dataType: 'json',
      async: false,
      success: function(data){
          db = data;
      },
      error : function () {
          alert('DB connection failed');
      }
  });</code></pre>
  </div>
  </div>
  </p>
  
  <p>Here's what my manifest.json file has for permissions (I also have the matches for good measure):</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>{
    "name": "My extension",
    ...
    "permissions": [
      "http://*/*",
      "https://*/*"
    ],
    ...
    "content_scripts": [ {
     ...
         "matches": [ 
     "http://*/*", "https://*/*", 
      "https://mail.google.com/mail/*", "http://mail.google.com/mail/*",
      "https://mail.google.com/*", "http://mail.google.com/*"
          ]
    }]
  }</code></pre>
  </div>
  </div>
  </p>