function test_alert() {
	alert('test');
}

/**
 * hides all sheets except the current (element) or hides the current element
 * 
 * @param	element		current sheet element id
 * @param	single		if true only the current element will be hidden
 */

function hide_sheets(element,single) {

	if(single) {
		sheet_ol = document.getElementById(sheets[element]['name']+'_overlay');
		sheet_ol.style.visibility = 'hidden';
		sheet_ol.style.zIndex = '0';
	} else {
		for(i=1; i < sheets.length; i++) {
			if(element != sheets[i]['name']) {
				curr_sheet = document.getElementById(sheets[i]['name']+'_overlay');
				curr_sheet.style.visibility = 'hidden';
				curr_sheet.style.zIndex = '0';
			}
		}
	}
}



/**
 * sets timout and calls function 'display_sheet"
 * 
 * @param	element		current sheet element id
 */

function display_sheet_timeout(element) {
	
	// set yellowbox.border-bottom to hover color
	inner_yellowbox = document.getElementById(sheets[element]['name']).getElementsByTagName('div')[0];
	inner_yellowbox.style.borderBottom = '2px solid '+sheets[element]['col_hover'];
	
	// call overlay sheet with delay of 0.5 sec.
	window.setTimeout('display_sheet(\''+element+'\',1)',300);
}


/**
 * does all css stuff to display an overlay sheet. Calls "hide_sheets" 
 * 
 * @param	element		current sheet element id
 */

function display_sheet(element) {
	
	
	// hide all other sheets that are maybe in hover state
	hide_sheets(element,0);
	
	// set yellowbox.border-bottom to default color
	inner_yellowbox = document.getElementById(sheets[element]['name']).getElementsByTagName('div')[0];
	inner_yellowbox.style.borderBottom = '2px solid '+sheets[element]['col_default'];
	
	// set unit_selector.border-bottom to hover color
	document.getElementById('unit_selector').style.borderBottom = '1px solid '+sheets[element]['col_hover'];
	
	// load left hover image
	img_left = document.getElementById('mainImage_left');
	img_left.style.backgroundPosition = "0px 0px";
	img_left.style.backgroundImage = "url(" + sheets[element]['image_1']+ ")";
	
	// change visbility and update z-index for overlay sheet
	sheet_ol = document.getElementById(sheets[element]['name']+'_overlay');
	sheet_ol.style.zIndex = '1000';
	sheet_ol.style.visibility = 'visible';
}


// image fade in functions
//-----------------------------------


function initImage() {
								
	curr_img_1 = document.getElementById('mainImage_left');
						
	curr_img_1.style.visibility = 'visible';
	
	fadeIn(curr_img_1.id,0);

}

function fadeIn(objId,opacity) {
	
	var obj = document.getElementById(objId);

	if (opacity <= 100) {
		
		// IE/Win
		//obj.style.filter = "alpha(opacity:"+opacity+")";
		
		// Safari<1.2, Konqueror
		obj.style.KHTMLOpacity = opacity/100;
		
		// Older Mozilla and Firefox
		obj.style.MozOpacity = opacity/100;
		
		// Safari 1.2, newer Firefox and Mozilla, CSS3
		obj.style.opacity = opacity/100;
		
		opacity += 10;
		
		window.setTimeout("fadeIn('"+objId+"',"+opacity+")", 100);
	}else if(opacity == 110)
	{
		obj.style.filter = "";
	}
}