title: open layer: display a label from properties in geojson file
body: <p>I am new to open layer map. I am trying to display a label on a marker by reading the label from a geojson file. </p>
  
  <p>Here is the format of my geojson file:</p>
  
  <pre><code>{
      "type": "FeatureCollection",
      "features": [
          {"type":"Feature","properties":{"label":"1"}, "geometry":{"type":"Point", "coordinates":[-81, 42]}},
      ]
  }
  </code></pre>
  
  <p>I tried to use attribute replacement to display the label. Here is the code:</p>
  
  <pre><code>var vector_style = new OpenLayers.Style({
          'fillColor': '#669933',
          'fillOpacity': .8,
          'strokeColor': '#aaee77',
          'strokeWidth': 3,
          'pointRadius': 8,
          'label': '${label}'
      });
  </code></pre>
  
  <p>However, all the other properties are shown except the label. Could you please tell me how I can display the label from the geojson file?</p>