CenterThat

CenterThat is a lightweight JavaScript utility designed to simplify the centering of elements on a webpage. It provides a consistent way to horizontally and vertically center content across a range of viewport sizes and devices, working alongside modern layout methods such as flexbox and CSS grid while offering fallback behavior for older browsers. The library targets common UI patterns such as modal dialogs, tooltips, and hero sections where precise centering is important.

Origin and licensing: CenterThat was released as an open-source project by a small collaborative group and has since gathered a community of contributors. The project is distributed under the MIT license and is maintained through a public repository where issues, requests, and improvements are discussed.

Features and approach: CenterThat provides a minimal API that can be applied with HTML attributes or class hooks. It can center elements along both axes using a data-center attribute (for example data-center='xy' to center on both axes) or a center-that class. It interoperates with existing CSS layouts and can detect dynamic content changes to re-calculate positioning. The library also provides basic accessibility considerations, ensuring that centered elements remain focusable and readable.

Usage notes: After including CenterThat in a page, apply the appropriate marker to the target element and let the library initialize. It is designed to work without dependency on a particular framework and can be integrated gradually into existing projects. As with any DOM-based utility, developers should test across devices to assess layout behavior within their specific design.

See also: CSS centering, Flexbox, CSS Grid, Web accessibility, Open-source JavaScript libraries.