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 contentHeight = document.getElementById('main').offsetHeight;
var footerElement = document.getElementById('footer');
var footerHeight  = footerElement.offsetHeight;
if (windowHeight - (contentHeight + footerHeight) >= 0) {
footerElement.style.position = 'absolute';
footerElement.style.top = (windowHeight - footerHeight) + 'px';
}
else {
footerElement.style.position = 'static';
}
}
}
}
window.onload = function() {
setFooter();
}
window.onresize = function() {
setFooter();
}