// verify all of the required fields were entered on the form
function checkForm(form){

var formPtr = document.forms[form], elemPtr;
for ( i=0; i<formPtr.length-1; i++ ){
   elemPtr=formPtr.elements[i];
   if (i == 7 && isNaN(elemPtr.value)){
      alert("Please enter a numeric value for zip code.");
      elemPtr.focus();
      return false;
   }
   if (elemPtr.value == ""){
      if(i == 0)
         alert("Please enter your first name.");
      else if(i == 1)
         alert("Please enter your last name.");
      else if(i == 2)
         alert("Please enter your email address.");
      else  // nothing else is required
         continue;
      elemPtr.focus();
      return false;
   }
}
return true;
}