function getParam(name)
{
  var pname=name+"=";
  var ps=window.location.search;
  if(ps.length>0)
  {
    var start=ps.indexOf(pname);
    if(start>-1)
      {
        start+=pname.length;
        var end=ps.indexOf('&',start);
        if(end==-1)
          end=ps.length;
        return unescape(ps.substring(start,end));
      }
  }
  return null;
}