var docwidth = 0;
var menuloc = 0;
var heightadj = 0;

function InitAllMenus(){
	InitMenu("aboutoff",140,190);
	InitMenu("fleetoff",178,190);
	InitMenu("mapoff",216,190);
	InitMenu("costoff",254,190);
	InitMenu("bookoff",292,190);
	InitMenu("abouton",140,190);
	InitMenu("fleeton",178,190);
	InitMenu("mapon",216,190);
	InitMenu("coston",254,190);
	InitMenu("bookon",292,190);
	if (ThisPage == "about")
		sLayer("abouton"); 
	else
		sLayer("aboutoff"); 
	if (ThisPage == "fleet")
		sLayer("fleeton"); 
	else
		sLayer("fleetoff"); 
	if (ThisPage == "map")
		sLayer("mapon"); 
	else
		sLayer("mapoff"); 
	if (ThisPage == "cost")
		sLayer("coston"); 
	else
		sLayer("costoff"); 
	if (ThisPage == "book")
		sLayer("bookon"); 
	else
		sLayer("bookoff"); 
}

function InitMenu(LayerName,offsetleft,offsettop){
	heightadj = 0;
	if(document.layers){
		docwidth = (window.innerWidth/2)+offsetleft;
		if (window.innerWidth<780) {
			docwidth = 390 + offsetleft;
			heightadj = 8;
		} 
		eval('document.layers["'+LayerName+'"].left = docwidth;')
		docheight = (window.innerHeight/2)-offsettop+heightadj;
		if (docheight<11) {docheight = 11}
		eval('document.layers["'+LayerName+'"].top = docheight;')
	}
	if(document.all){
		docwidth = (document.body.clientWidth/2)+offsetleft;
		if (document.body.clientWidth<780) {
			docwidth = 390 + offsetleft;
			heightadj = 8;
		} 
		eval('document.all["'+LayerName+'"].style.left = docwidth;')
		docheight = (document.body.clientHeight/2)-offsettop+heightadj;
		if (docheight<11) {docheight = 11}
		eval('document.all["'+LayerName+'"].style.top = docheight;')
	}
	if(!document.all && document.getElementById){
		docwidth = (innerWidth/2)+offsetleft;
		if (innerWidth<780) { 
			docwidth = 390 + offsetleft;
			heightadj = 8;
		} 
		document.getElementById(LayerName).style.left = docwidth;
		docheight = (innerHeight/2)-offsettop-1;
		if (docheight<11) {docheight = 11}
		document.getElementById(LayerName).style.top = docheight;
	}
}

function doButtons(name,pic) {
	document[name].src=pic;
}

function sLayer(layerName) {	
  if (document.getElementById) {
      document.getElementById(layerName).style.visibility = 'visible';
  }
  else if (document.layers && document.layers[layerName] != null) {
      document.layers[layerName].visibility = 'visible';
  }
  else if (document.all) {
      document.all[layerName].style.visibility = 'visible';
  }
  return false;
}

function hLayer(layerName) {
  if (document.getElementById) {
      document.getElementById(layerName).style.visibility = 'hidden';
  }
  else if (document.layers && document.layers[layerName] != null) {
      document.layers[layerName].visibility = 'hidden';
  }
  else if (document.all) {
      document.all[layerName].style.visibility = 'hidden';
  }
  return false;
}