addLoadListener(equalHeight);

function equalHeight() {

var myLeftColumn = document.getElementById("maincontent");
var myRightColumn = document.getElementById("sidemenu");

var myLeftHeight = myLeftColumn.offsetHeight;
var myRightHeight = myRightColumn.offsetHeight;

var myLeftBorderTopPixels = PropertyStringToNumber(retrieveComputedStyle(myLeftColumn, "borderTopWidth"));
var myLeftBorderBottomPixels = PropertyStringToNumber(retrieveComputedStyle(myLeftColumn, "borderBottomWidth"));
var myLeftPaddingTopPixels = PropertyStringToNumber(retrieveComputedStyle(myLeftColumn, "paddingTop"));
var myLeftPaddingBottomPixels = PropertyStringToNumber(retrieveComputedStyle(myLeftColumn, "paddingBottom"));

var myRightBorderTopPixels = PropertyStringToNumber(retrieveComputedStyle(myRightColumn, "borderTopWidth"));
var myRightBorderBottomPixels = PropertyStringToNumber(retrieveComputedStyle(myRightColumn, "borderBottomWidth"));
var myRightPaddingTopPixels = PropertyStringToNumber(retrieveComputedStyle(myRightColumn, "paddingTop"));
var myRightPaddingBottomPixels = PropertyStringToNumber(retrieveComputedStyle(myRightColumn, "paddingBottom"));

var myLeftBorderNumber = Number(myLeftBorderTopPixels.replace("px", "")) + Number(myLeftBorderBottomPixels.replace("px", ""));
var myLeftPaddingNumber = Number(myLeftPaddingTopPixels.replace("px", "")) + Number(myLeftPaddingBottomPixels.replace("px", ""));
var myLeftExtras = myLeftBorderNumber + myLeftPaddingNumber;

var myRightBorderNumber = Number(myRightBorderTopPixels.replace("px", "")) + Number(myRightBorderBottomPixels.replace("px", ""));
var myRightPaddingNumber = Number(myRightPaddingTopPixels.replace("px", "")) + Number(myRightPaddingBottomPixels.replace("px", ""));
var myRightExtras = myRightBorderNumber + myRightPaddingNumber;

	if (myLeftHeight > myRightHeight) {
		myRightColumn.style.height = (myLeftHeight - myRightExtras) + "px";
	}
	else {
		myLeftColumn.style.height = (myRightHeight - myLeftExtras) + "px";
	}
	
}
function isNumber(a) { return +a == a }

function PropertyStringToNumber(str){
	if (isNumber(str.replace("px", ""))){
		return str;
	} else {
		if (str=="thin") return "1px";
		else if (str=="medium") return "3px";
		else if (str=="thick") return "5px";
		else return "0px";
	}
}

function retrieveComputedStyle(element, styleProperty)
{
		var computedStyle = null;
		
		if (typeof element.currentStyle != "undefined")
		{
			computedStyle = element.currentStyle;
		}
		else
		{
			computedStyle = document.defaultView.getComputedStyle(element, null);
		}
		
		return computedStyle[styleProperty];
}

function addLoadListener(fn)
{
	if (typeof window.addEventListener != 'undefined')
	{
	window.addEventListener('load', fn, false);
}
else if (typeof document.addEventListener != 'undefined')
{
	document.addEventListener('load', fn, false);
}
else if (typeof window.attachEvent != 'undefined')
{
	window.attachEvent('onload', fn);
}
else
{
	var oldfn = window.onload;
	if (typeof window.onload != 'function')
	{
	window.onload = fn;
	}
	else
	{
	window.onload = function()
	{
	oldfn();
	fn();
	};
	}
	}
}