function centerWin(url, name, width, height) {
 var str = "height=" + height + ",innerHeight=" + height;
 str += ",width=" + width + ",innerWidth=" + width;
 if (window.screen) {
  var ah = screen.availHeight - 30;
  var aw = screen.availWidth - 10;
  var xc = (aw - width) / 2;
  var yc = (ah - height) / 2;
  str += ",left=" + xc + ",screenX=" + xc;
  str += ",top=" + yc + ",screenY=" + yc;
  str += ",scrollbars=yes";
 }
 return window.open(url, name, str);
}
function showhide(id){
 if (document.getElementById){
  obj = document.getElementById(id);
 if (obj.style.display == "none"){
  obj.style.display = "";
  } else {
  obj.style.display = "none";
  }
 }
}