Client-side validation

Editor, in general, assumes that server-side validation of the data will be performed and any errors will be reported back to the client (the validation must be done at the server anyway for security, so this saves duplicating logic). However, there are cases where performing client-side checks can be very valuable, particularly if you want to avoid the overhead of making an Ajax request that contains known error information.

There are a number of methods for doing this with Editor, including simply not calling the submit() method when you don't want to submit the data, but this example shows how client-side validation can be achieved using the preSubmit event which can be used to cancel the submit by returning false.

The preSubmit event is used to run a custom function just before the data is submitted to the server. The error() method is used to show the error message to the end user, if required, and inError() to determine if the form shows an error state and thus not submit the form.

The validation performed here uses field().isMultiValue() to first determine if a field has multiple values or not - if it does, then no additional validation is performed since the end user can't have entered a value (when using the UI a multi-value edit effects all items being edited). If the user has entered a value (field().val()) it is checked to be not empty and <20 characters in length.

Note that the event handlers functions are executed in the Editor instance's scope, so API methods can be accessed using the this keyword.

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

Javascript
HTML
CSS
Ajax
Server-side script
Comments

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

var 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'
});

editor.on('preSubmit', function (e, o, action) {
	if (action !== 'remove') {
		var firstName = this.field('first_name');

		// Only validate user input values - different values indicate that
		// the end user has not entered a value
		if (!firstName.isMultiValue()) {
			if (!firstName.val()) {
				firstName.error('A first name must be given');
			}

			if (firstName.val().length >= 20) {
				firstName.error(
					'The first name length must be less that 20 characters'
				);
			}
		}

		// ... additional validation rules

		// If any error was reported, cancel the submission so it can be corrected
		if (this.inError()) {
			return false;
		}
	}
});

$('#example').DataTable({
	ajax: '../php/staff.php',
	columns: [
		{
			data: null,
			render: function (data, type, row) {
				// Combine the first and last names into a single table field
				return data.first_name + ' ' + data.last_name;
			}
		},
		{ data: 'position' },
		{ data: 'office' },
		{ data: 'extn' },
		{ data: 'start_date' },
		{ data: 'salary', render: DataTable.render.number(null, null, 0, '$') }
	],
	layout: {
		topStart: {
			buttons: [
				{ extend: 'create', editor: editor },
				{ extend: 'edit', editor: editor },
				{ extend: 'remove', editor: editor }
			]
		}
	},
	select: true
});

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'
});

editor.on('preSubmit', function (e, o, action) {
	if (action !== 'remove') {
		let firstName = this.field('first_name');

		// Only validate user input values - different values indicate that
		// the end user has not entered a value
		if (!firstName.isMultiValue()) {
			if (!firstName.val()) {
				firstName.error('A first name must be given');
			}

			if (firstName.val().length >= 20) {
				firstName.error(
					'The first name length must be less that 20 characters'
				);
			}
		}

		// ... additional validation rules

		// If any error was reported, cancel the submission so it can be corrected
		if (this.inError()) {
			return false;
		}
	}
});

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 interaction for this demo is shown below. This server uses PHP, so the PHP script is shown, however our download packages include the equivalent script for other platforms, including .NET and Node.js. Server-side scripts can be written in any language, using the protocol described in the Editor documentation.

Client-side validation

Other examples

Simple initialisation

Advanced initialisation

DataTables as an input

Dates and time

DataTables extensions

Inline editing

Bubble editing

API

Standalone

Styling

Plug-ins

DataTables