The <input type="radio"> HTML element represents one button in a group such that only one can be chosen at a time.

The <input type="reset"> HTML element represents a button that sets all form fields to their initial values.

The <input type="submit"> HTML element represents a button that triggers an action on its associated <form>, such as sending the form data to a server.

The <input type="email">, <input type="tel">, and <input type="url"> HTML elements represent email address, telephone number, and URL fields in a form.

The <input type="text"> HTML element allows the user to enter information into a form. By default, an <input> element is a text input.

The pageshow and pagehide transition events fire when a document loads or unloads due to a navigation, such as clicking on a link on a page or the back button in a browser.

The document.visibilityState and document.hidden properties tell you whether the page is visible to the user (for example, it's not minimized or in a background tab).

The @charset CSS at-rule specifies the character encoding of an external style sheet.

The float CSS property aligns an element to either side of its container, allowing text and inline elements to flow around it. The clear CSS property sets whether an element is moved below floating elements that proceed it.

The vertical-align CSS property sets the vertical alignment of inline, inline-block, and table cell elements. It has no effect on block-level elements.

The :empty CSS pseudo-class matches elements without child elements.

The :lang() CSS functional pseudo-class matches elements based on their content language.

The :root pseudo-class matches the root element of the document, usually the <html> element.

The :target CSS pseudo-class matches the element with an ID matching the URL fragment.

The :checked, :disabled, and :enabled CSS pseudo-classes match form elements based on their state.

The :active, :focus, and :hover CSS pseudo-classes match elements based on how users are interacting with them.

The :nth-of-type() and :nth-last-of-type() CSS functional pseudo-classes match elements based on their position among siblings of the same type. The :first-of-type, :last-of-type, and :only-of-type pseudo-classes match the first, last, and only elements of its type.

The form validity CSS pseudo-classes match <form> elements based on the constraints of a form field, such as validity (:valid, :invalid, :in-range, :out-of-range) and necessity (:optional or :required).

The background-image CSS property sets the graphics to display behind the content of an element and in front of the background color. Graphics may be any combination of images or gradients.

The background-origin CSS property sets the background starting position relative to the border and padding of an element.

The background-position CSS property offsets the initial position of background images relative to the background origin.

The box-shadow CSS property applies shadow effects around an element's frame. This can create drop shadow and inner shadow effects.

The WEBGL_depth_texture extension for WebGL 1.0 contexts defines 2D depth and depth-stencil textures.

The attr() CSS function, in content property declarations, sets a ::before or ::after pseudo-element's content to the value of the specified HTML attribute.

The DOM (Document Object Model) API represents HTML and XML documents as trees of nodes. You can use the API to inspect and modify the structure and content of a document.

The MutationObserver API watches for changes to the DOM tree and calls a callback function when DOM changes occur.

The text-shadow CSS property sets the position and styles of shadow on text.

The getComputedStyle() global method returns an CSSStyleDeclaration object that represents all CSS declarations applied to a given element.

The navigator.language property is a string representing the preferred language of the user, usually the language of the browser UI. The navigator.languages property is an array of strings representing the user's preferred languages.

The window.navigator API is a generic global object, under which many other, more interesting APIs are located. It doesn't do anything interesting on its own.