function setHeight () {
	var main = document.getElementById ('main');
	var left = document.getElementById ('left');
	var right = document.getElementById ('right');
	
	if (! main) return;
	/*if (! left) return;
	if (! right) return;*/
	
	var height = main.offsetHeight;
	if (left) left.style.height = height + 'px';
	if (right) right.style.height = height + 'px';
}

function installMainHeight () {
	setHeight();
}

function fixDocHeight () {
	var doc = document.body.clientHeight;
	var header = document.getElementById( 'header' ).offsetHeight;
	var main = document.getElementById( 'main' ).offsetHeight;
	var footer = document.getElementById( 'footer' ).offsetHeight;
	var diff = doc - header - main - footer;
	
	if ( diff > 0 ) document.getElementById( 'main' ).style.minHeight = ( main + diff ) + 'px';
}

if ( window.addEventListener ) window.addEventListener ( 'load', installMainHeight, false );
else if ( window.attachEvent ) window.attachEvent ( 'onload', installMainHeight );

if ( window.addEventListener ) window.addEventListener ( 'load', fixDocHeight, false );
else if ( window.attachEvent ) window.attachEvent ( 'onload', fixDocHeight );