// preload images
	var menu1 = new Image();
	var menu2 = new Image();
	var menu3 = new Image();
	var menu4 = new Image();
	var menu1h = new Image();
	var menu2h = new Image();
	var menu3h = new Image();
	var menu4h = new Image();
	
	menu1.src = '/img/gui/topmenu_signedandinscribed.gif';
	menu2.src = '/img/gui/topmenu_modernfirsteditions.gif';
	menu3.src = '/img/gui/topmenu_manuscripts.gif';
	menu4.src = '/img/gui/topmenu_antiquarianbooks.gif';
	menu1h.src = '/img/gui/topmenu_signedandinscribedh.gif';
	menu2h.src = '/img/gui/topmenu_modernfirsteditionsh.gif';
	menu3h.src = '/img/gui/topmenu_manuscriptsh.gif';
	menu4h.src = '/img/gui/topmenu_antiquarianbooksh.gif';
	
	function menuover( num ) {
	
		var theimage = new Image();
	
		if( num == 1 ) {
		
			theimage.src = menu1h.src;
		
		}
		else if( num == 2 ) {
		
			theimage.src = menu2h.src;
		
		}
		else if( num == 3 ) {
		
			theimage.src = menu3h.src;
		
		}
		else if( num == 4 ) {
		
			theimage.src = menu4h.src;
		
		}
		
		document.getElementById( 'menu' + num ).src = theimage.src;
	
	}
	
	function menuout( num ) {
	
		var theimage = new Image();
	
		if( num == 1 ) {
		
			theimage.src = menu1.src;
		
		}
		else if( num == 2 ) {
		
			theimage.src = menu2.src;
		
		}
		else if( num == 3 ) {
		
			theimage.src = menu3.src;
		
		}
		else if( num == 4 ) {
		
			theimage.src = menu4.src;
		
		}
		
		document.getElementById( 'menu' + num ).src = theimage.src;
	
	}
	
	function tablerollover( column ) {
	
		// show column
		document.getElementById( 'home1x' + column ).style.visibility = 'visible';
		document.getElementById( 'home2x' + column ).style.visibility = 'visible';
		
		// highlight top menu
		menuover( column );
		
		// make link bold
		document.getElementById( 'label' + column ).style.fontWeight = 'bold';
	
	}
	
	function tablerollout() {
	
		document.getElementById( 'home1x1' ).style.visibility = 'hidden';
		document.getElementById( 'home1x2' ).style.visibility = 'hidden';
		document.getElementById( 'home1x3' ).style.visibility = 'hidden';
		document.getElementById( 'home1x4' ).style.visibility = 'hidden';
		document.getElementById( 'home2x1' ).style.visibility = 'hidden';
		document.getElementById( 'home2x2' ).style.visibility = 'hidden';
		document.getElementById( 'home2x3' ).style.visibility = 'hidden';
		document.getElementById( 'home2x4' ).style.visibility = 'hidden';
		
		menuout( 1 );
		menuout( 2 );
		menuout( 3 );
		menuout( 4 );
		
		document.getElementById( 'label1' ).style.fontWeight = '100';
		document.getElementById( 'label2' ).style.fontWeight = '100';
		document.getElementById( 'label3' ).style.fontWeight = '100';
		document.getElementById( 'label4' ).style.fontWeight = '100';
	
	}