function setMainHeight()
{
	var headerHeight = 138;

	var main = document.getElementById('main');
	var windowHeight = getWindowHeight();

	var minMainHeight = windowHeight - headerHeight;	
	if(main.offsetHeight < minMainHeight)
	{
		main.style.height = minMainHeight + "px";
	}
}

/// returns the height of the viewport
function getWindowHeight()
{
	if (self.innerHeight) // all except Explorer
	{
		return self.innerHeight;
	}
	else if (document.documentElement && document.documentElement.clientHeight)
		// Explorer 6 Strict Mode
	{
		return document.documentElement.clientHeight;
	}
	else if (document.body) // other Explorers
	{
		return document.body.clientHeight;
	}
}


/// Append an eventlistener. Eventname may follow either the form "onclick" or "click"
function AddEventListener(obj, eventName, eventDelegate)
{
	if(window.addEventListener)
	{
		eventName = (eventName.substr(0, 2).toLowerCase() == "on")
			? eventName.substr(2) : eventName;

		obj.addEventListener(eventName, eventDelegate, false);
	}
	else // IE
	{
		eventName = (eventName.substr(0, 2).toLowerCase() == "on")
			? eventName : "on" + eventName;
		obj.attachEvent(eventName, eventDelegate);
	}
}