var elementWidth = this.width;
var elementHeight = this.height;
var viewport = dijit.getViewport();
// compute the centered position var x = viewport.l + (viewport.w - elementWidth)/2;
var y = viewport.t + (viewport.h - elementHeight)/2;
// set the centered positionvar container = dojo.byId(this.id + "Container");
container.style.top = y + "px";
container.style.left = x + "px";