function checkrentals() {
 
  rsendto = document.rentalbook.sendto.options[document.rentalbook.sendto.selectedIndex].value;
  rname = document.rentalbook.name.value;
  rphone = document.rentalbook.phone.value;
  rmobile = document.rentalbook.mobile.value;
  rdatefrom = document.rentalbook.datefrom.value;
  rdateto = document.rentalbook.dateto.value;
  rrequire = document.rentalbook.require.options[document.rentalbook.require.selectedIndex].value;
  reventtype = document.rentalbook.eventtype.options[document.rentalbook.eventtype.selectedIndex].value;
  remail = document.rentalbook.email.value;
  filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
  
 returnval = true;
 hideAllErrors();
if (rsendto == "select") {
 returnval = false;
 document.getElementById("sendtoError").style.display = "inline";
}
if (rname == "") {
 returnval = false;
 document.getElementById("nameError").style.display = "inline";
} 
if (rphone == "" && rmobile == "") {
 returnval = false;
 document.getElementById("phoneError").style.display = "inline";
} 
if (rdatefrom == "" || rdateto == "") {
 returnval = false;
 document.getElementById("dateError").style.display = "inline";
} 
if (rrequire == "") {
 returnval = false;
 document.getElementById("requireError").style.display = "inline";
} 
if (reventtype == "select") {
 returnval = false;
 document.getElementById("eventtypeError").style.display = "inline";
} 
if (remail == "") {
 returnval = false;
 document.getElementById("emailError").style.display = "inline";
}
if (remail != "" && !(filter.test(remail))) { 
 returnval = false;
 document.getElementById("emailError").style.display = "none";
 document.getElementById("email2Error").style.display = "inline";
}

 return returnval;
}
 
function hideAllErrors() {
document.getElementById("sendtoError").style.display = "none";
document.getElementById("emailError").style.display = "none";
document.getElementById("email2Error").style.display = "none";
document.getElementById("nameError").style.display = "none";
document.getElementById("phoneError").style.display = "none";
document.getElementById("dateError").style.display = "none";
document.getElementById("requireError").style.display = "none";
document.getElementById("eventtypeError").style.display = "none";
}