title: OpenLayers2 No 'Access-Control-Allow-Origin' header error
body: <p>I am trying to update a (several year old) OL2 JS app with a new OSM layer</p>
  
  <p>My layer code is:</p>
  
  <pre><code>                        var osm = new OpenLayers.Layer.OSM(
                                  "Hydda",
                                  ["http://a.tile.openstreetmap.se/hydda/full/${z}/${x}/${y}.png"],
                                  {crossOriginKeyword: null}
                          )
  </code></pre>
  
  <p>I cannot get the tiles to load without the following error:</p>
  
  <blockquote>
    <p>Image from origin '<a href="http://a.tile.openstreetmap.se" rel="nofollow">http://a.tile.openstreetmap.se</a>' has been blocked
    from loading by Cross-Origin Resource Sharing policy: No
    'Access-Control-Allow-Origin' header is present on the requested
    resource. Origin '<a href="http://mysite" rel="nofollow">http://mysite</a>' is therefore not allowed access.</p>
  </blockquote>
  
  <p>Any ideas? The crossOriginKeyword declaration should handle this, right? </p>