
The WebClass "listbox" is used to display a list of values with the
<select> tag of HTML. These values are taken from a recordset (which
can be retrieved from DB or can be supplied by PHP code. The recodset 
associated with the listbox must have two fields: 'id' and 'label'.
'label' is the field displayed, and 'id' is the value that is selected,
saved in DB and retrieved from DB.

Recordset example:
  <Recordset ID="listbox::country">
    <Query>
      SELECT country_id AS id, country_name AS label
      FROM countries
    </Query>
  </Recordset>

Usage example:
  <Include SRC="{{#LISTBOX_PATH}}listbox.html" />
  <WebObject Class="listbox" Name="country" 
             rs       = "rs_id"
         onchange = "alert(this.options[this.selectedIndex].text)"
         width    = "---------------" />

The attribute "rs" is optional. Its default value (if not specified) is
{{#obj_id}} (in the example above, it would be 'listbox::country').

The attribute "onchange" (all lowercase), is optional and is used as 
the "onchange" attribute of the <select> tag.

The attribute "width" is also optional; it is used as the last line of the
list, in order to keep the width of the <select> to a certain size, and
can also be used as a "nothing selected" (none of the above) value.

This WebClass uses a <select> tag like this:
    <select name="{{#obj_name}}" onchange="{{#onchange}}">
      . . . . .
    </select>
So, this should be kept in mind when accessing the selected value
and when giving an initial value.
If the 'listbox' is used inside a 'formWebObj' webbox, then it 
takes care of it automatically.
