=====================
on_field_select_value
=====================

on_field_select_value(field, lookup_item)

**domain**: client 

**language**: javascript

**class** :doc:`Item class </refs/client/item_api>`

Description
===========

When user clicks on the button to the right of the field input or uses typeahead,
the application creates a copy of the lookup item of the field and
triggers ``on_field_select_value`` event. Use ``on_field_select_value`` to 
specify fields that will be displayed, set up filters for the lookup item, before
it will be opened.

The ``field`` parameter is the field whose data will be selected.

The ``lookup_item`` parameter is a copy of the lookup item of the field

Example
=======

.. code-block:: js

    function on_field_select_value(field, lookup_item) {
        if (field.field_name === 'customer') {
            lookup_item.set_where({lastname__startwith: 'B'});
            lookup_item.view_options.fields = ['firstname', 'lastname', 'address', 'phone'];
        }
    }


See also
========

:doc:`Fields </programming/data/fields>`

:doc:`Lookup fields </programming/data/lookup_fields>`