function getParam(paramName) {
  var href=window.location.href
  var pos=href.indexOf("&"+paramName+"=")
  if (pos==-1) {
    pos=href.indexOf("?"+paramName+"=")
  }
  var cam=""
  if (pos>=0) {
    href=href.substring(pos+paramName.length+2)
    var end=href.indexOf("&")
    if (end==-1) {
      end = href.length
    }
    cam=href.substring(0, end)
  }
  return( unescape(cam.replace(/\+/g, " ")))
}