if (window.addEventListener){
	window.addEventListener("load", initPage, false);
	window.addEventListener("resize", initPageHeight, false);
}
else if (window.attachEvent){
	window.attachEvent("onload", initPage);
	window.attachEvent("onresize", initPageHeight);
}

function initPage(){
	initPageHeight();
}

function initPageHeight(){
	document.getElementById("main").style.height = document.body.clientHeight - 
				document.getElementById("header").offsetHeight - document.getElementById("footer").offsetHeight + 'px';
}