//handy function in javascript

function getVisibleWindowSize() {
	var myWidth = 0, myHeight = 0;
	if( typeof( window.innerWidth ) == 'number' ) {
		//Non-IE
		myWidth = window.innerWidth;
		myHeight = window.innerHeight;
	} else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
		//IE 6+ in 'standards compliant mode'
		myWidth = document.documentElement.clientWidth;
		myHeight = document.documentElement.clientHeight;
	} else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
		//IE 4 compatible
		myWidth = document.body.clientWidth;
		myHeight = document.body.clientHeight;
	}
	return [myWidth, myHeight]
}

function getPageSize() {
	var xScroll, yScroll, windowWidth, windowHeight;
	var windowSize = getVisibleWindowSize();
	
	windowWidth = windowSize[0];
	windowHeight = windowSize[1];
	
	if (window.innerHeight && window.scrollMaxY) {	
		xScroll = window.innerWidth + window.scrollMaxX;
		yScroll = window.innerHeight + window.scrollMaxY;
	} else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
		xScroll = document.body.scrollWidth;
		yScroll = document.body.scrollHeight;
	} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
		xScroll = document.body.offsetWidth;
		yScroll = document.body.offsetHeight;
	}
	
	// for small pages with total height less then height of the viewport
	if (yScroll < windowHeight) {
		pageHeight = windowHeight;
	} else { 
		pageHeight = yScroll;
	}
	// for small pages with total width less then width of the viewport
	if (xScroll < windowWidth) {	
		pageWidth = xScroll;		
	} else {
		pageWidth = windowWidth;
	}
	return [pageWidth, pageHeight];
}

function getScrollOffsets() {
	var scrollOffset = document.viewport.getScrollOffsets();
	return [scrollOffset[0], scrollOffset[1]];
}