function getHeight(id) {
	// shamelessly filched from http://www.forum4designers.com/archive22-2004-5-82532.html
	var obj=document.getElementById(id);
	var objHeight=null;
	if(document.implementation.hasFeature("CSS", "2.0")) {
		objHeight=document.defaultView.getComputedStyle(obj,null).getPropertyCSSValue("height").getFloatValue(5);
	}
	else if(obj.clientHeight!=null) {
		objHeight=obj.offsetHeight;
	}
	return parseInt(objHeight)+20;
}

function changePadding() {
	document.body.style.paddingTop=getHeight("header")+'px';
	document.body.style.paddingBottom=getHeight("footer")+'px';
}

init=function() {
	changePadding();
}

window.onload=init;