function getWindowHeight() {
	var windowHeight = 0;
	if (typeof(window.innerHeight) == 'number') {
		windowHeight = window.innerHeight;
	}
	else {
		if (document.documentElement && document.documentElement.clientHeight) {
			windowHeight = document.documentElement.clientHeight;
		}
		else {
			if (document.body && document.body.clientHeight) {
				windowHeight = document.body.clientHeight;
			}
		}
	}
	return windowHeight;
}

function setFooter() {
	if (document.getElementById) {
		var windowHeight = getWindowHeight();
		if (windowHeight > 0) {
			var containerElement = document.getElementById('container') 
			var contentHeight = containerElement.offsetHeight;
			var footerElement = document.getElementById('footer');
			var footerHeight  = footerElement.offsetHeight;
			if (windowHeight > contentHeight) {
				footerElement.style.position = 'absolute'
				footerElement.style.top = (windowHeight - footerHeight) + 'px'
				containerElement.style.height = windowHeight + 'px'
			}
		}
	}
}

window.onload = function() {
	setFooter();
}
window.onresize = function() {
	setFooter();
}