function showLayer(layerid) { 

    layer = document.getElementById(layerid); 
    layer.style.visibility = "visible";  
    keepMenu(); 
} 

function showOneLayer(layerid) { 
     
    // remove any open menus 
	
	layer = document.getElementById('About'); 
    layer.style.visibility = "hidden"; 
	layer = document.getElementById('Expertise'); 
    layer.style.visibility = "hidden"; 
	layer = document.getElementById('Management'); 
    layer.style.visibility = "hidden"; 
	layer = document.getElementById('News'); 
    layer.style.visibility = "hidden"; 
	layer = document.getElementById('Contact'); 
    layer.style.visibility = "hidden"; 
     
    showLayer(layerid) 
} 


function hideLayer(layerid) { 
    layer = document.getElementById(layerid); 
    layer.style.visibility = "hidden"; 
} 


var timer; 


function keepMenu() { 
    clearTimeout(timer); 
} 

function hideMenus(s) { 
    timer = setTimeout("hideLayer('" + s + "')", 400); 
}