The <form> element
A web page's <form> element is used to create a form on the page, collect user data and send that data to an application for processing. For example, when you shop online, you fill out a form indicating the product and the number of items and then submit it for processing. The DOM HTMLFormElement Interface provides the properties and methods. Forms must have a unique name Forms also must contain a method which says how the data will be sent to the application. Examples show how to use the post and get methods to send user data to an application.
Try it
It is possible to use the :valid and :invalid CSS pseudo-classes to style a <form> element based on whether the elements inside the form are valid.