function checkParent( src, tagName )
	{
		while ( src != null ) {
			if (src.tagName == tagName) 
				return src;
			src = src.parentElement;
		}
		return null;
	}

	
	function checkContent( src, tagName )
	{
		var pos = src.sourceIndex ;
		while ( src.contains( document.all[++pos] ) )
			if ( document.all[pos].tagName == tagName )
				return document.all[pos] ;
		return null ;
	}
      
	
	function Main()
	{     
		var src = event.srcElement ;
		var item = checkParent( src, "LI" ) ;

		if ( parent != null ) {
			var content = checkContent( item, "UL" ) ;

			if ( content != null )
				if ( content.style.display == "" )
					content.style.display = "block" ;
				else
					content.style.display = "" ;
		}
		event.cancelBubble = true;
	}