HTMLFormularValidierung

HTMLFormularVa... appears to be an incomplete or nonstandard term. In standard web development, the relevant concept is HTML forms, which are defined by the form element and used to collect user input from a user interface.

An HTML form is identified by the form element, which can specify a submission method via the method attribute (GET or POST) and a destination URL via the action attribute. The enctype attribute determines how data is encoded when sent; for example, application/x-www-form-urlencoded is common, while multipart/form-data is required for file uploads.

Form controls include input elements, select boxes, textareas, and buttons. Each control should be associated with a label, using the label element and the for attribute to improve accessibility. Common input types include text, email, password, number, date, checkbox, radio, file, and hidden, among others. The form can be grouped with fieldset and legend for readability and accessibility.

HTML5 adds client-side validation through attributes such as required, minlength, pattern, and step. JavaScript can enhance behavior, but forms should still be functional with no scripts for accessibility. On submission, server-side validation is essential to enforce rules and sanitize input. Security considerations include using HTTPS and protecting against CSRF.

Common variants of HTML forms include contact forms, login forms, search forms, and multi-step wizards, as well as forms that support file uploads. Good practice emphasizes accessibility, progressive enhancement, and proper error messaging.