//
// Copyright (c) Art. Lebedev | http://www.artlebedev.ru/
// Author - Vladimir Tokmakov
//

function InitTopNavigation(){
	var eTopNavDiv = document.getElementById( 'TopNavigation' )
	if( eTopNavDiv ){
		var aeNavItem = eTopNavDiv.getElementsByTagName( 'A' )
		
		var sImgSrc, bIsIlluminated, img

		for( var i = 0; i < aeNavItem.length; i++ ){
			img = aeNavItem[i].getElementsByTagName( 'IMG' )[0]
			if( img ){
				sImgSrc = img.src
				bIsIlluminated = sImgSrc.search(/[^\-][^a]\.(gif|jpg)$/) == -1
				if( !bIsIlluminated && img.id != 'TNI-logo' ){
					aeNavItem[i].onmouseover = IlluminateTopNavItem
					aeNavItem[i].onmouseout  = IlluminateTopNavItem
				}
			}
		}
	}
}


function IlluminateTopNavItem(e){
	var eCurrent = e ? e.target : window.event.srcElement
	var evtCurrent = e ? e : window.event

	var sImgSrc = eCurrent.getAttribute( 'src' )
	if( evtCurrent.type == 'mouseover' ){
		eCurrent.setAttribute( 'src', sImgSrc.replace(/\.(gif|jpg)$/, '-a.$1') )
	}else if( evtCurrent.type == 'mouseout' ){
		eCurrent.setAttribute( 'src', sImgSrc.replace(/(-a)\.(gif|jpg)$/, '.$2') )
	}
}

window.onload = InitTopNavigation