var imgNow;
var RollImages = new Array;

function setImages(subdir){
	if (document.images) {
		addImage(1,subdir+"nav_about_rol.gif", subdir+"nav_about.gif");
		addImage(2,subdir+"nav_companies_rol.gif", subdir+"nav_companies.gif");
		addImage(3,subdir+"nav_activity_rol.gif", subdir+"nav_activity.gif");
		addImage(4,subdir+"nav_partners_rol.gif", subdir+"nav_partners.gif");
		addImage(5,subdir+"nav_events_rol.gif", subdir+"nav_events.gif");
		addImage(6,subdir+"nav_news_rol.gif", subdir+"nav_news.gif");
		addImage(7,subdir+"nav_login_rol.gif", subdir+"nav_login.gif");
	}
}

function addImage(ind,srcon,srcoff){
	key = "img"+ind+"on";
	RollImages[key] = new Image();
	RollImages[key].src = srcon;
	key = "img"+ind+"off";
	RollImages[key] = new Image();
	RollImages[key].src = srcoff;
}

function imgOn(imgName) {
	if (document.images) {
 		document[imgName].src = RollImages[imgName+"on"].src; 
	}
}

function imgOff(imgName) {
	if (document.images) {
		if (imgName != imgNow) {
			document[imgName].src = RollImages[imgName+"off"].src; 
		} 
	} 
}