function challengeSinglesValidate() {
   var sError = "";
   
   if (isEmpty(document.singles.matchDate.value)) {
        sError = sError + "Match Date is required\n";
   } else {
     if (validateDate(document.singles.matchDate.value,"U","F") == false) {
        sError = sError + "Match Date is not a valid format or is in the past\n";
     }
   }
   
   if (!isEmpty(sError)) {
      alert(sError);
      return false;
   } else {
      return true;
   }
}

function challengeDoublesValidate() {
   var sError = "";
   
   if (isEmpty(document.doubles.matchDate.value)) {
        sError = sError + "Match Date is required\n";
   } else {
     if (validateDate(document.doubles.matchDate.value,"U","F") == false) {
        sError = sError + "Match Date is not a valid format or is in the past\n";
     }
   }
   
   if (!isEmpty(sError)) {
      alert(sError);
      return false;
   } else {
      return true;
   }
}