Openlayers with proj4.js and custom Projection

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/openlayers/2.11/OpenLayers.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/proj4js/1.1.0/proj4js-combined.js"></script>
Openlayers with proj4.js and custom Projection
<div id="map"></div>

CSS

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

JavaScript

var projection= new OpenLayers.Projection("EPSG:3301");
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("Maa/ameti aluskaart",
            "http://kaart.maaamet.ee/wms/alus?",{layers: 'MA-ALUS',
                version: '1.1.1' ,'srs':projection});
map.addLayer(base);
map.setCenter(new OpenLayers.LonLat(25.567422, 58.885704).transform(new OpenLayers.Projection("EPSG:4326"),projection),2);