function VDM_getRefToDiv(divID,oDoc) {
	if( !oDoc ) { oDoc = document; }
	if( document.layers ) {
		if( oDoc.layers[divID] ) { return oDoc.layers[divID]; } else {
			//repeatedly run through all child layers
			for( var x = 0, y; !y && x < oDoc.layers.length; x++ ) {
				//on success, return that layer, else return nothing
				y = getRefToDiv(divID,oDoc.layers[x].document); }
			return y; } }
	if( document.getElementById ) {
		return document.getElementById(divID); }
	if( document.all ) {
		return document.all[divID]; }
	return false;
}


//globals
var main_layer_handle, shadow_layer_handle, info_iframe_handle, last_URL;

function open_info_iframe(URL, height_requested)
	{
	//get info iframe reference
	vdm_info_iframe = VDM_getRefToDiv('info_iframe');

	//get id references
	main_layer = VDM_getRefToDiv('Layer1');
	shadow_layer = VDM_getRefToDiv('Layer2');

	//change height
	main_layer.style.height = height_requested + "px";
	shadow_layer.style.height = height_requested + "px";
	vdm_info_iframe.style.height = height_requested + "px";

	//position layers relative to calling element (only height)
	height = (((self.screen.availHeight - height_requested) / 2) * 0.7) + Scroll_Top();	//"0.7" = for positioning it not dead center
	main_layer.style.top = height + "px";
	shadow_layer.style.top = (height+3) + "px";

	//save layers
	main_layer_handle = main_layer;
	shadow_layer_handle = shadow_layer;
	info_iframe_handle = vdm_info_iframe;

	//show layers
	if(last_URL != URL)	
		{
		vdm_info_iframe.src = URL;
		show_layers();
		}
	else
		{
		vdm_info_iframe.src = URL;
		main_layer_handle.style.visibility = 'visible';
		shadow_layer_handle.style.visibility = 'visible';
		}
	last_URL = URL;
	}

function show_layers()
	{
	main_layer_handle.style.visibility = 'visible';
	shadow_layer_handle.style.visibility = 'visible';
	}
	
function close_info_iframe()
	{
	//show layers
	main_layer_handle.style.visibility = 'hidden';
	shadow_layer_handle.style.visibility = 'hidden';
	info_iframe_handle.src = "kunden_info/leere_seite.html";
	}	
	
	

function Scroll_Top ()
	{
	if (self.pageYOffset) // all except Explorer
		return self.pageYOffset;
	else if (document.documentElement && document.documentElement.scrollTop)
		// Explorer 6 Strict
		return document.documentElement.scrollTop;
	else if (document.body) // all other Explorers
		return document.body.scrollTop;
	}