/*
-> Index fängt immer bei 0 an (also auch bei den IDs der Elemente)
-> Hauptmenüpunkte müssen ID 'mainmenu#' haben
-> Unterpunkte müssen ID 'submenu#' haben
*/


var step = 6;						// um wieviel soll das Subfenster wachsen
var delay = 2;						// wie schnell 
var maxSubHeight = 110;				// max Höhe eines Subpunkts
var maxMenu = 4;					// Anzahl der Menüpunkt
var actHeight = new Array();		// akt. Höhe eines Subelements


function initSubMenu()
{
	var offsetTop;
	var offsetLeft;						
	var offsetParent;

	for(i=0;i<maxMenu;i++)
	{
		// dient zur Berechnung der Position des Unterpunktes
		offsetTop = document.getElementById("mainmenu" + i).offsetTop + document.getElementById("mainmenu" + i).height;
		offsetLeft = document.getElementById("mainmenu" + i).offsetLeft;
		offsetParent = document.getElementById("mainmenu" + i).offsetParent;
		
		while(offsetParent) 
		{
			offsetTop += offsetParent.offsetTop;
			offsetLeft += offsetParent.offsetLeft;
			offsetParent = offsetParent.offsetParent;
		}
		
		// Alle Subpunkte auf Höhe 0 setzen & neu positionieren
		actHeight[i] = 0;
		document.getElementById("submenu"+i).style.height = "0px";
		document.getElementById("submenu"+i).style.left = offsetLeft + "px";
		document.getElementById("submenu"+i).style.top = offsetTop + "px";
		document.getElementById("submenu"+i).style.width = document.getElementById("mainmenu" + i).width + "px";
		document.getElementById("submenu"+i).style.visibility = "hidden";
	}
}

function showSubMenu(id)
{
	for(i=0;i<maxMenu;i++)
	{
		if(i==id)
			actHeight[id] += step;
		else
			actHeight[i] -= step;
		
		if(actHeight[id] > maxSubHeight)
			actHeight[id] = maxSubHeight;
			
		if(actHeight[i] < 0)
		{
			actHeight[i] = 0;
			document.getElementById("submenu"+i).style.visibility = "hidden";
		}
		else
			document.getElementById("submenu"+i).style.visibility = "visible";

		
		document.getElementById("submenu"+i).style.height = actHeight[i] + "px";
	}
	
	if(actHeight[id] < maxSubHeight)
	{
		setTimeout("showSubMenu('" + id + "')",delay);
	}
}

window.onresize = initSubMenu;