var prevPage = "";
var curPage = "";

if (document.images)
{   	
	    next_on = new Image();
        next_on.src = "grafiki/przycisk_dalej.gif";
        next_off = new Image();
        next_off.src = "grafiki/przycisk_dalej_n.gif";

		powrot_on = new Image();
        powrot_on.src = "grafiki/przycisk_wstecz.gif";
        powrot_off = new Image();
        powrot_off.src = "grafiki/przycisk_wstecz_n.gif";		
		
		powrot2_on = new Image();
        powrot2_on.src = "grafiki/powrot_przy.gif";
        powrot2_off = new Image();
        powrot2_off.src = "grafiki/powrot_przy_n.gif";	

		wej_on = new Image();
        wej_on.src = "images/wej_2_03.gif";
        wej_off = new Image();
		wej_off.src = "images/wej__03.gif";	

		wyj_on = new Image();
        wyj_on.src = "images/wej_2_05.gif";
        wyj_off = new Image();
		wyj_off.src = "images/wej__05.gif";	

}

function imgOn(itemName)
{
	if (document.images) {
		document[itemName].src = eval(itemName + "_on.src");
	}
}

function imgOff(itemName)
{	
	if (document.images && curPage != itemName) {
		document[itemName].src = eval(itemName + "_off.src");
	}

}

function centerWindow(pageUrl,pageTitle,pageWidth,pageHeight,pageSet) 
{ if(screen){ 
var page_width = pageWidth; 
var page_height = pageHeight; 
var page_set = pageSet; 
var page_top = (screen.height-page_height)/2; 
var page_left = (screen.width-page_width)/2; 
openPage=window.open(''+ pageUrl + '',''+ pageTitle + '','width=' + page_width + ',height=' + page_height + ',top=' + page_top + ',left=' + page_left + ',pageSet=' + page_set + ''); 
openPage.focus(); 
} else { 
openPage=window.open(''+ pageUrl + '',''+ pageTitle + ''); 
openPage.focus(); 
} 
}