function CheckFields()
  {
    var s_message = "";

    if (document.request_form.FirstName.value.length < 2) {s_message += "First Name\n";}
    if (document.request_form.LastName.value.length < 2) {s_message += "Last Name\n";}
    if (document.request_form.Email.value.length < 6) {s_message += "E-mail\n";}
    if (!parseInt(document.request_form.Quantity.value)) {s_message += "Quantity\n";}

    if (s_message != "") {
      s_message = "Fill in the following field(s) with proper values, please:\n\n" + s_message;
      alert(s_message);
      return false;
    }

    if (document.request_form.Email.value!="")  {
    if (document.request_form.Email.value.indexOf("@")==-1 ||
        document.request_form.Email.value.indexOf(".")==-1 ||
        document.request_form.Email.value.indexOf(" ")== 1 ||
        document.request_form.Email.value.length<6){
       alert("Sorry, Your email address is not valid.");
       document.request_form.Email.focus();return false;
     }
  }
  pmt=document.request_form.Payment;
  pmt_checked=false;
     for(var i=0; i<pmt.length;i++){if (pmt[i].checked) pmt_checked=true;}
    if (!pmt_checked) {alert( "Choose your payment method, please.");return false;}
  return true;
  }