# Editor example Events - unsaved changes close confirmation

When editing large forms it can be frustrating if the form were to be accidentally closed by clicking on the background before submitting the changes. To address this, you can use the events provided by Editor to check if a user has closed the form without saving changes, and ask them to confirm if this is what they want to do.

This is done by using the `open` and `preBlur` events, in combination with the `get()`. When passed no parameters this API method will give you the values for all fields in the form, as an object. As such, when the form is opened (`open`) the values of the form in that opening state can easily be saved for comparison later.

Later, when the form is closed by clicking on the page background the `preBlur` event is emitted and allows you to cancel the closing action by returning `false` from the event handler's function (note that `preClose` could also be used, and would be activated by a click on the close icon as well).

At this point a simple comparison can be performed using `get()`'s current return value and the values that were previously saved allowing us to ask the user if they really want to discard their changes.

Name | Position | Office | Extn. | Start date | Salary
--- | --- | --- | --- | --- | ---
Name | Position | Office | Extn. | Start date | Salary

- JavaScript
- HTML
- CSS
- Ajax
- Server-side script

The JavaScript shown below is used to initialise the table shown in this example:

`const editor = new DataTable.Editor({ ajax: '../php/staff.php', fields: [ { label: 'First name:', name: 'first_name' }, { label: 'Last name:', name: 'last_name' }, { label: 'Position:', name: 'position' }, { label: 'Office:', name: 'office' }, { label: 'Extension:', name: 'extn' }, { label: 'Start date:', name: 'start_date', type: 'datetime' }, { label: 'Salary:', name: 'salary' } ], table: '#example' }); let openVals; editor .on('open', function () { // Store the values of the fields on open openVals = JSON.stringify(editor.get()); editor.on('preClose', function (e) { // On close, check if the values have changed and ask for closing confirmation if they have if (openVals !== JSON.stringify(editor.get())) { return confirm( 'You have unsaved changes. Are you sure you want to exit?' ); } }); }) .on('postCreate postEdit close', function () { editor.off('preClose'); }); new DataTable('#example', { ajax: '../php/staff.php', columns: [ { data: null, render: (data) => data.first_name + ' ' + data.last_name }, { data: 'position' }, { data: 'office' }, { data: 'extn' }, { data: 'start_date' }, { data: 'salary', render: DataTable.render.number(null, null, 0, '$') } ], layout: { topStart: { buttons: [ { extend: 'create', editor: editor }, { extend: 'edit', editor: editor }, { extend: 'remove', editor: editor } ] } }, select: true });`

In addition to the above code, the following JavaScript library files are loaded for use in this example:

The HTML shown below is the raw HTML table element, before it has been enhanced by DataTables:

This example uses a little bit of additional CSS beyond what is loaded from the library files (below), in order to correctly display the table. The additional CSS used is shown below:

``

The following CSS library files are loaded for use in this example to provide the styling of the table:

This table loads data by Ajax. The latest data that has been loaded is shown below. This data will update automatically as any additional data is loaded.

The script used to perform the server-side processing for this table is shown below. Please note that this is just an example script using PHP. Server-side processing scripts can be written in any language, using the protocol described in the DataTables documentation.