form validation trouble

Hi I'm trying to validate a form but I'm having problems validating the radio buttons and the select menu (or options menu).
Here's the code I tried:

<script language="javascript" type="text/javascript">
function validate_required(field,alerttxt)
{
with (field)
{
if (value==null||value=="")
  {alert(alerttxt);return false;}
else {return true}
}
}
function validate_radio(radio,alerttext){
with (radio)
{
if (!radio.checked){
   alert(alerttext);return false;}
   
   else {return true;}
   }
}

   
function validate_dropdown(drop,alerttext){
with(drop){
if (value=="Please Choose..."){alert(alerttext);return false;}

else {return true;}
}
}
function validate_form(thisform)
{
with (thisform)
{
  
if (validate_required(screen,"Screenname must be filled out!")==false)
  {screen.focus();return false;}
  
if (validate_required(first,"You must have a first name.")==false)
  {first.focus();return false;}
   
if (validate_required(last,"you must have a last name.")==false)
  {last.focus();return false;}
   
if (validate_required(age,"How old are you?")==false)
  {age.focus();return false;}
   
if (validate_required(occupation,"Please provide a school or occupation")==false)
  {occupation.focus();return false;}

if (validate_required(email,"Email must be filled out!")==false)
  {email.focus();return false;}
  
if (validate_required(phone,"Please Provide a phone number.")==false)
  {phone.focus();return false;}
  
if (validate_radio(rent,"Are you renting a computer?")==false)
  {rent.focus();return false;}
  
if (validate_radio(pizza,"Please Choose a type of pizza")==false)
  {pizza.focus();return false;}

if (validate_dropdown(city,"Please choose a city")==false)
  {pizza.focus();return false;}
}
}
</script>

Code (markup):

Any idea why the radio buttons and the option menu validation isn't working?
Much appreciated.
- Derek

 

Have you tried the suggestions made by hrcerqueira on your another thread about this topic: http://forums.digitalpoint.com/showpost.php?p=5450055&postcount=6 ?

 

no I didn't notice that reply ajsa, thanks.