Form validation

Type

The type attribute of the <input> elements describes the behavior and validation constraints of the input.

http://www.w3schools.com/html/html_form_input_types.asp

HTML Input Types

On some devices, the virtual keyboard will be adapted to the type of the input.

Validation

By default, a form can not be submitted until all inputs are valid.

It is possible to use additional attributes like maxlength, minlength, pattern or required to apply some additional constraints.

The validity property of the <input> element can be used in JavaScript to check input's validity and eventually, the invalidity reason.

const input = document.querySelector('input');

input.validity.valid; // false
input.validity.valueMissing; // true

It is possible to disable native validation using the form's novalidate attribute.

This can be used to validate the form manually or using a JavaScript library or framework.