var map;
var swipe;

function init() {

    map = new OpenLayers.Map({
        div : "map",
        allOverlays : true
    });

    var osm = new OpenLayers.Layer.OSM();
    var gmap = new OpenLayers.Layer.Google("Google Streets");

    map.addLayers([ osm, gmap ]);

    swipe = new OpenLayers.Control.Swipe(osm);

    map.addControl(swipe);

    map.setCenter(new OpenLayers.LonLat(10.2, 48.9).transform(new OpenLayers.Projection("EPSG:4326"), map.getProjectionObject()), 9);
}

function toggleControl(element) {
    if (element.checked) {
        swipe.activate();
    } else {
        swipe.deactivate();
    }
}