var map;
      OpenLayers.IMAGE_RELOAD_ATTEMPTS = 3;
      OpenLayers.ImgPath = "http://js.mapbox.com/theme/dark/";
      window.onload = function init() {

        // Customize the values below to change the tileset.
        // This information is available on each tileset page.
        var layername = 'world-light';
        var file_extension = 'png';

        // Build the map
        var options = {
          projection: new OpenLayers.Projection("EPSG:900913"),
          displayProjection: new OpenLayers.Projection("EPSG:4326"),
          units: "m",
          numZoomLevels: 12,
          maxResolution: 156543.0339,
          maxExtent: new OpenLayers.Bounds(
            -20037500,
            -20037500,
            20037500,
            20037500
          )
        };
        map = new OpenLayers.Map('map', options);

        // Layer definitions
        var layer = new OpenLayers.Layer.TMS(
          "MapBox Layer",
          [ "http://a.tile.mapbox.com/","http://b.tile.mapbox.com/",
            "http://c.tile.mapbox.com/","http://d.tile.mapbox.com/" ],
          { 'layername': layername, 'type': file_extension }
        );

        // Add layers to the map
        map.addLayers([ layer ]);

        // Set the map's initial center point
        map.setCenter(new OpenLayers.LonLat(0, 0), 1);
      }