================
on_before_append
================

on_before_append(item)

**domain**: client 

**language**: javascript

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

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

Occurs before an application inserts or appends a record.

The ``item`` parameter is an item that triggered the event.

Write an on_before_append event handler to take specific action immediately before 
an application inserts or appends a record in an item. on_before_append is called 
by :doc:`insert <m_insert>` or :doc:`append <m_append>` method. If the event returns 
false, the operation is aborted. 

See also
========

:doc:`Modifying datasets </programming/data/modifying_datasets>`
