afterbegin

Afterbegin is a keyword used in several DOM insertion methods to specify where new content should be inserted relative to an element. It is one of the four insertion positions accepted by insertAdjacentHTML, insertAdjacentElement, and insertAdjacentText: beforebegin, afterbegin, beforeend, and afterend.

When used with an element, afterbegin inserts the supplied content immediately after the opening tag, making it the first child of the element. If the element already contains children, the new content becomes the first child; if the element is empty, the content becomes the only child.

Example: given a div that currently contains the text Hello, applying insertAdjacentHTML('afterbegin', '<span>Hi</span>') would result in a structure like <div><span>Hi</span>Hello</div>.

Compatibility: The insertion methods that use the afterbegin position are supported in all modern major browsers. Older or very old browsers that do not implement these methods may not recognize this position.

Notes: Afterbegin is a positional keyword that, in common use, is passed as a string argument to the relevant insertion methods, guiding where the new content should be placed within the target element. It is part of a set of related positions that control insertion relative to the element versus around it.