title: [Javascript]Get coordinate from openlayers map
body: <p>I would get the coordinate from an openlayers map.
  When I open my page I would that when I click on a button, I have received the coordinate of top bottom left and the upper right.</p>
  
  <pre><code> &lt;html&gt;
  &lt;head&gt;
    &lt;title&gt;OpenLayers Example&lt;/title&gt;
      &lt;script src="http://openlayers.org/api/OpenLayers.js"&gt;&lt;/script&gt;
      &lt;/head&gt;
      &lt;body&gt;
        &lt;div style="width:100%; height:100%" id="map"&gt;&lt;/div&gt;
        &lt;script defer="defer" type="text/javascript"&gt;
          var map = new OpenLayers.Map('map');
          var wms = new OpenLayers.Layer.WMS( "OpenLayers WMS",
              "http://labs.metacarta.com/wms/vmap0", {layers: 'basic'} );
          map.addLayer(wms);
          map.zoomToMaxExtent();
        &lt;/script&gt;
  &lt;input type="button" text="Get Coordinate from map"&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>Thanks a lot.</p>