function verifyPoll(oPoll) {
  //verify at least one response checked ... 
  var cElem=oPoll.elements; 
  var bPoll=false;
  for (e=0;e<cElem.length;e++) {
    if(cElem[e].type=="radio" && cElem[e].checked) {
      bPoll=true;
      break;
    }
  }
  if (bPoll) {
    //open window ... 
    var wPoll=window.open('about:blank','pollWindow','top=36,left=36,width=650,height=450,resizable=yes,scrollbars=yes');
    wPoll.focus();
    //set target
    oPoll.target="pollWindow";
    return true;
  } else {
    alert("Merci de cocher une reponse.");
    return false;
  }
}