function feedback_onsubmit()
{
   var ok = false;

   if( document.feedback.Name.value == "" )
   {
      	alert( "Please enter your name." );
     	document.feedback.Name.focus();
   }
   else if( validName( document.feedback.Name.value ) == false )
   {
	alert( "Name must contain alphabetic characters only." );
	document.feedback.Name.focus();
   }
   else if( document.feedback.phone.value != "" &&
	    validPhone( document.feedback.phone.value ) == false )
   {
      	alert( "Telehone number must be in the format xxx-xxx-xxxx." );
	document.feedback.phone.focus();
   }
   else if( document.feedback.Email.value != "" &&
	    validEmail( document.feedback.Email.value ) == false )
   {
      	alert( "Email address must be in the format name@provider.xyz." );
	document.feedback.Email.focus();
   }
   else if( document.feedback.phone.value == "" &&
	    document.feedback.Email.value == "" ) 
   {
	alert( "You must fill in either an email address or a phone number." );
   }
   else
   {
	ok = true;
   }

   return ok;
}