HTTP/1.1 is a network protocol used by browsers and servers. It has been superseded by HTTP/2 and HTTP/3.

WebVTT is a captions and subtitles format. WebVTT files are loaded using the <track> element, and the VTTCue API can be used to create or update cues dynamically.

The array splice() method changes an array in-place. You can use it to delete items, overwrite items, or insert items, starting from an index.

The Array.isArray() static method checks whether a value is an array.

The autofocus HTML attribute gives focus to an element on page load.

The Strict-Transport-Security HTTP response header informs browsers that the site should only be accessed using HTTPS, and that any future attempts to access it using HTTP should automatically be converted to HTTPS. Also known as HSTS.

The OES_element_index_uint extension for WebGL 1.0 contexts adds support for gl.UNSIGNED_INT types to WebGLRenderingContext.drawElements().

The OES_standard_derivatives extension for WebGL 1.0 contexts adds the GLSL derivative functions dFdx, dFdy, and fwidth.

The OES_texture_float extension for WebGL 1.0 contexts adds floating-point pixel types for textures.

The OES_texture_float_linear extension for WebGL 1.0 and 2.0 contexts adds linear filtering with floating-point pixel types for textures.

The <s> HTML element indicates text that is no longer relevant or accurate, styling text as strikethrough by default.

The <bdo> element overrides the directionality of text, so that the text within is rendered in a different direction than the surrounding text.

The <del> element represents a range of text that has been deleted from a document, styling text as strikethrough by default.

The <kbd> element represents textual user input, such as keyboard or voice input, styling text in monospaced type by default.

The <nav> element represents a section of a page whose purpose is to provide navigation links, either within the current document or to other documents.

The <wbr> HTML element represents a word break opportunity, to explicitly mark a place within a word where a line might be broken.

The <article> element represents self-contained content, which is intended to be independently distributable or reusable, such as a comment, a blog post, or news article.

The <section> element is a generic standalone section of a document, which doesn't have a more specific semantic element to represent it.

The <cite> element represents the title of a quoted, referenced, or mentioned creative work, such as a film or book.

The <pre> element represents a block element of preformatted text that is presented exactly as written, including all white space.

The <samp> element represents a sample or quoted output from a computer program. Styled in a monospace font by default.

The <small> element represents side-comments and small print, like copyright and legal text, independent of its styled presentation. Styled in a reduced font size by default.

The <h1> through <h6> HTML elements represent six levels of section headings, in order of decreasing importance.

The <title> element sets the title of the document and exposes it to users via the UI of the browser or app they're using and through assistive technology.

The <u> HTML element makes non-textual annotations, styling text as underlined by default.

The background-clip CSS property sets the extent of the background: the padding box, the content box, or the default border box.

The calc() CSS function computes mathematical expressions such a calc(100%/3 - 1em).

The text-indent CSS property sets the size of the empty space (indentation) at the beginning of lines in a text.

The <abbr> HTML element represents an abbreviation or acronym.

The <address> element represents contact information for a person or people, or for an organization.