function ajax(pagina,query,objecto)
{
var xmlHttp;
//document.getElementById("fundo").style.backgroundColor="black";
document.getElementById(objecto).innerHTML='<center><div style="vertical-align: middle;"><img src="Imagens/ajax-loader.gif" border=0> a processar...</div></center>';

try
  {
  // Firefox, Opera 8.0+, Safari
  xmlHttp=new XMLHttpRequest();
  }
catch (e)
  {
  // Internet Explorer
  try
    {
    xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
    }
  catch (e)
    {
    try
      {
      xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
    catch (e)
      {
      alert("O seu browser nao suporta o AJAX!");
      return false;
      }
    }
  }
  

  xmlHttp.onreadystatechange=function()
   {
    if(xmlHttp.readyState==4)
      {   
	  document.getElementById(objecto).innerHTML=xmlHttp.responseText;
      }
    }
  xmlHttp.open("GET",pagina+query,true);
  xmlHttp.send(null);
  }

function GetSelectedItem() {

chosen = ""
len = document.f1.r1.length

for (i = 0; i <len; i++) {
if (document.f1.r1[i].checked) {
chosen = document.f1.r1[i].value
}
}

if (chosen == "") {
return -1;
}
else {
return chosen; 
}
}