OpenLayers example from chapter 1 of "OpenLayers 2.10" by Eric Hazard, translated to Jade

openlayers_ch1.jade

doctype 5
html
  head
    title My OpenLayers Map
    script(src='OpenLayers.js')
    script
      function init() {
        map = new OpenLayers.Map('map_element', {});
        var wms = new OpenLayers.Layer.WMS(
          'OpenLayers.WMS',
          'http://vmap0.tiles.osgeo.org/wms/vmap0',
          {layers: 'basic'},
          {});

        map.addLayer(wms);
        if (!map.getCenter()) {
          map.zoomToMaxExtent();
        }
      }

  body(onload='init();')
    #map_element(style='width: 500px; height: 500px;')