function chgzone(choice)
{
  var tz = choice.options[choice.selectedIndex].value;
  if (tz) {
    if (location.href.indexOf("?") == -1) {
      newurl = location.href + "?tz=" + tz;
      location.href = newurl;
    } else {
      if (location.search.indexOf("tz=") == -1) {
        newurl = location.href + "&tz=" + tz;
        location.href = newurl;
      } else {
        if (location.search.indexOf("?tz=") == -1) {
          var loc = location.href.indexOf("&tz=");
          newurl = location.href.substring(0,loc) + "&tz=" + tz;
          location.href = newurl;
        } else {
          var loc = location.href.indexOf("?tz=");
          newurl = location.href.substring(0,loc) + "?tz=" + tz;
          location.href = newurl;
        }          
      }
    }
  }
}

function setselected() {
  var czone = getCookie("zone");
  document.zone.tz.selectedIndex = (czone == null || czone == "") ? 0 : czone - 1;
  if (location.search.indexOf("EST5EDT") != -1) document.zone.tz.selectedIndex = 0;
  if (location.search.indexOf("CST6CDT") != -1) document.zone.tz.selectedIndex = 1;
  if (location.search.indexOf("MST7MDT") != -1) document.zone.tz.selectedIndex = 2;
  if (location.search.indexOf("PST8PDT") != -1) document.zone.tz.selectedIndex = 3;
}