OpenLayers Transform Function

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/openlayers/2.11/OpenLayers.js"></script>
<body onload="init()">
    <div id="transformation">Centerpoint 4326:
        <div id="centerpoint4326"></div>
        <br />Centerpoint 3857:
        <div id="centerpoint3857"></div>
        <br />
        <button value="zoom to point2" onclick="myFunction()">Zoom To Point 2</button> 
            
    </div>
    <div id="map"></div>
</body>

CSS

#map {
    width: 600px;
    height: 600px;
}
#transformation div {
    font-weight:bold;
}
button
{
    margin-bottom:10px;
    
}

JavaScript

var lon = 13.31576;
var lat = 52.3209;

var zoom = 16;

var map;

function init() {
    map = new OpenLayers.Map('map', {
        maxExtent: new OpenLayers.Bounds(-20037508.34, -20037508.34, 20037508.34, 20037508.34)
    });
    var vlayer = new OpenLayers.Layer.Vector("Point", {
        displayOutsideMaxExtent: true
    });
    map.addLayers([new OpenLayers.Layer.OSM(), vlayer]);

    var center_4326 = new OpenLayers.LonLat(lon, lat);

    document.getElementById("centerpoint4326").innerHTML = center_4326.toString();

    var centerpoint = center_4326.transform(
    new OpenLayers.Projection("EPSG:4326"),
    map.getProjectionObject());


    document.getElementById("centerpoint3857").innerHTML = centerpoint.toString();
    
    // wgs84-coordinates that need to be reprojected
    var point1 = new OpenLayers.Feature.Vector(
    new OpenLayers.Geometry.Point(lon, lat).transform(new OpenLayers.Projection("EPSG:4326"),
    map.getProjectionObject()));
    
    // epsg3857-Coordinates without the need to reproject
    var point2 = new OpenLayers.Feature.Vector(
    new OpenLayers.Geometry.Point(4193332, 7486473));

    vlayer.addFeatures([point1,point2]);
    console.log(vlayer.features[0]);
    map.addControl(new OpenLayers.Control.LayerSwitcher());
    map.setCenter(centerpoint, zoom);


}


function myFunction() {
var lat = 7486473; 
var lon = 4193332;
var lonlat = new OpenLayers.LonLat(lon, lat);
map.setCenter(lonlat);
    
}