Openlayers with proj4.js and custom Projection

HTML

<script src="//cdnjs.cloudflare.com/ajax/libs/openlayers/2.13.1/OpenLayers.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/proj4js/2.3.3/proj4.js "></script>
Openlayers with proj4.js and custom Projection
<div id="map"></div>

Mark to myself:
SCHROTT / LOESCHEN
CRAP // DELETE jsfiddle

CSS

#map
{
    width:500px;
    height: 500px;
    
}

JavaScript

window.Proj4js = {
        Proj: function(code) {
          return proj4(Proj4js.defs[code]);
        },
        defs: proj4.defs,
        transform: proj4
      };
     // Definition comes from http://epsg.io/31466/
      proj4.defs["EPSG:31466"] = "+proj=tmerc +lat_0=0 +lon_0=6 +k=1 +x_0=2500000 +y_0=0 +ellps=bessel +towgs84=598.1,73.7,418.2,0.202,0.045,-2.455,6.7 +units=m +no_defs";
      console.log(Proj4js.defs["EPSG:31466"]);

      var proj_wgs84 = new OpenLayers.Projection("EPSG:4326");
      var projection = new OpenLayers.Projection("EPSG:31466");
      // Center for projection EPSG:31466
      var point = new OpenLayers.LonLat(2769212.70, 5678724.61);
      var new_point= point.transform(projection, proj_wgs84);
      console.log(new_point.lat, new_point.lon);




var bounds = new OpenLayers.Bounds(
            370753.1145, 6382922.7769, 739245.6000, 6624811.0577
    );
    var options = {
        maxExtent: bounds,
        maxResolution: 2601.4538070271437,
        projection:projection,
        units: 'm'
    };
    map = new OpenLayers.Map('map', options);
var base  = new OpenLayers.Layer.WMS("Regierungsbezirk",
            "http://sg.geodatenzentrum.de/wms_dgm200?",{layers: 'DGM200',
                version: '1.3.0', srs:projection});
map.addLayer(base);
map.setCenter(point,2);