/**
 * Returns inner dimensions (content size) of window
 * @return Object with properties 'width' and 'height' or null,
           if dimensions can't be retrieved
 * @author CB
 * @version 2006-09-09
 */
function windowDimensions() {

	if (self.innerHeight) {
		return {width: self.innerWidth, height: self.innerHeight};
	}
	
	if (document.documentElement && document.documentElement.clientHeight) {
		return {width: document.documentElement.clientWidth, height: document.documentElement.clientHeight};
	}
	
	if (document.body) {
		return {width: document.body.clientWidth, height: document.body.clientHeight};
	}

	return null;

} // function windowDimensions()