function aali_join_validateJoin() {

   var isOk;
   var password1;
   var radioGroup;
   var index;
   var value;

   isOk = true;
   if (isOk) {
      value = document.aali_join_form.username.value;
      value = value.replace(/^\s+/,'').replace(/\s+$/,'');
      isOk = (value.length > 0);
      if (!isOk) {
         alert("Please enter a username.");
      } else {
         isOk = ("abcdefghijklmnopqrstuvwxyz0123456789".indexOf(value.toLowerCase().charAt(0)) >= 0);
         if (!isOk) {
            alert("Your username must start with a letter.");
         } else {
            for (index = 1; index < value.length; ++index) {
               isOk = ("abcdefghijklmnopqrstuvwxyz0123456789_".indexOf(value.toLowerCase().charAt(index)) >= 0);
               if (!isOk) {
                  alert("Your username may only contain letters, digits, or the '_' character.");
                  break;
               }
            }
         }
      }
   }
   if (!isOk) {
      document.aali_join_form.username.focus();
      return(isOk);
   }
   if (isOk) {
      value = document.aali_join_form.password.value;
      value = value.replace(/^\s+/,'').replace(/\s+$/,'');
      isOk = (value.length > 0);
      if (!isOk) {
         alert("Please enter a password.");
      } else {
         password1 = value;
      }
   }
   if (!isOk) {
      document.aali_join_form.password.focus();
      return(isOk);
   }
   if (isOk) {
      value = document.aali_join_form.password2.value;
      value = value.replace(/^\s+/,'').replace(/\s+$/,'');
      isOk = (value.length > 0);
      if (!isOk) {
         alert("Please enter your password twice.");
      } else {
         isOk = (value == password1);
         if (!isOk) {
            alert("Please type the password twice correctly.");
         }
      }
   }
   if (!isOk) {
      document.aali_join_form.password2.focus();
      return(isOk);
   }
   if (isOk) {
      value = document.aali_join_form.email.value;
      value = value.replace(/^\s+/,'').replace(/\s+$/,'');
      isOk = (value.length > 0);
      if (!isOk) {
         alert("Please enter your email address.");
      }
   }
   if (!isOk) {
      document.aali_join_form.email.focus();
      return(isOk);
   }
   return(isOk);
}