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) {
        	// contentHeight ==> All Contents + footer
        	if(document.getElementById('containerPage')) {
	            var contentHeight=document.getElementById('containerPage').offsetHeight;
	            var footerElement=document.getElementById('footer');
	            var footerHeight=footerElement.offsetHeight;
		        if (windowHeight-contentHeight>=0) {
		            footerElement.style.position='relative';
		            footerElement.style.top=
		            (windowHeight-contentHeight)+'px';
		        }
		        else {
		            footerElement.style.position='static';
		        }
		    }
		}
	}
}

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