function writeSessionCookie (cookieName, cookieValue) {
  if (testSessionCookie()) {
    document.cookie = escape(cookieName) + "=" + escape(cookieValue) + "; path=/";
    return true;
  }
  else return false;
}

function getCookieValue (cookieName) {
  var exp = new RegExp (escape(cookieName) + "=([^;]+)");
  if (exp.test (document.cookie + ";")) {
    exp.exec (document.cookie + ";");
    return unescape(RegExp.$1);
  }
  else return null;
}

function testSessionCookie () {
  document.cookie ="testSessionCookie=Enabled";
  if (getCookieValue ("testSessionCookie")=="Enabled")
    return true;
  else
    return false;
}

function setpageYOffset() 
{
  if (document.all) y = document.body.scrollTop; 
  else              y = window.pageYOffset; 
  writeSessionCookie("pageYOffset", y); 
}

function resetpageYOffset() 
{
  writeSessionCookie("pageYOffset", 0);
}

function scrollTopageYOffset() 
{
  if (testSessionCookie()) {
    var y = getCookieValue("pageYOffset");
    if (y != null) window.scrollTo(0,y); 
    writeSessionCookie("pageYOffset", y);
  }
}

function undoScrollTopageYOffset() 
{
  window.scrollTo(0,0);
}