Called when user opens grid settings (on grids toolbar) and selects an item.
columnOnOff(el, event, field, value)

el | DOM Element, related element, often a checkbox
event | object, optional, DOM Event Object
field | string, field associated with the checkbox
value | integer, number of records to skip

Returns undefined value.

#### Description

This method is called when user opens grid settings menu and selects an item, normally to show/hide columns, but also to apply skip records and column width reset. The grid will emit the .onColumnOnOff event.
If you have grid defined in the following way: $('#grid').w2grid({ name : 'grid', show : { toolbar: true }, columns: [ { field: 'recid', caption: 'ID', size: '50px' }, { field: 'lname', caption: 'Last Name', size: '30%' }, { field: 'fname', caption: 'First Name', size: '30%' }, { field: 'email', caption: 'Email', size: '40%' }, { field: 'sdate', caption: 'Start Date', size: '120px' }, { field: 'sdate', caption: 'End Date', size: '120px' } ], onColumnOnOff: function (event) { console.log(event); }, records: [ { recid: 1, fname: 'John', lname: 'doe', email: 'vitali@gmail.com', sdate: '1/3/2012' }, { recid: 2, fname: 'Stuart', lname: 'Motzart', email: 'jdoe@gmail.com', sdate: '2/4/2012' }, { recid: 3, fname: 'Jin', lname: 'Franson', email: '--', sdate: '4/23/2012' }, { recid: 4, fname: 'Susan', lname: 'Ottie', email: 'jdoe@gmail.com', sdate: '5/3/2012' }, { recid: 5, fname: 'Kelly', lname: 'Silver', email: 'jdoe@gmail.com', sdate: '4/3/2012' }, { recid: 6, fname: 'Francis', lname: 'Gatos', email: 'vitali@gmail.com', sdate: '2/5/2012' } ] });