function convertWithin(vWithin) {
		var oWithin;

		if (typeof vWithin === "string") {
			oWithin = document.querySelector(vWithin);
		} else if (vWithin instanceof Element) {
			oWithin = vWithin.getDomRef();
		} else  {
			oWithin = vWithin;
		}

		return oWithin || window;
	}
Convert the different types of 'within' values to a DOM element or the window object.

@param {string | sap.ui.core.Element | Element | Window} [vWithin] the given within
@returns {Element | Window} the DOM element or Window object that represents the given within
@private