var corr = 516;

function locat() {
  if (navigator.appName.indexOf("Microsoft Internet Explorer") != -1) { corr = 520 } ;   
  var adj = (screen.availWidth - corr)/2;
  document.getElementById("mnubar").style.left = adj+"px";
  document.getElementById("mnubar").style.visibility = 'visible';
  var adjHor = document.getElementById("mnubar").offsetLeft;
  var adjVer = document.getElementById("mnubar").offsetTop;
  document.getElementById("mn1").style.left = adjHor+"px";
  document.getElementById("mn1").style.top = (adjVer+28)+"px";
  document.getElementById("mn2").style.left = (adjHor+100)+"px";
  document.getElementById("mn2").style.top = (adjVer+28)+"px";
  document.getElementById("mn3").style.left = (adjHor+225)+"px";
  document.getElementById("mn3").style.top = (adjVer+28)+"px";
  document.getElementById("mn4").style.left = (adjHor+350)+"px";
  document.getElementById("mn4").style.top = (adjVer+28)+"px";
}


var mnus = new Array(5); 
 mnus[1] = "mn1";
 mnus[2] = "mn2";
 mnus[3] = "mn3";
 mnus[4] = "mn4";


var mnuact = null;

function show(e) {
  if (mnuact == null) {
    objNavMenu = document.getElementById(mnus[e]);  
    objNavMenu.style.visibility = 'visible';
    mnuact= e;
  }
  else if (mnuact == e) {
    objNavMenu = document.getElementById(mnus[mnuact]);  
    objNavMenu.style.visibility = 'hidden';
    menuact = null;
  }
  else {
    objNavMenu = document.getElementById(mnus[mnuact]);  
    objNavMenu.style.visibility = 'hidden';
    objNavMenu = document.getElementById(mnus[e]);  
    objNavMenu.style.visibility = 'visible';
    mnuact= e;
  }
}