jQuery is a fast, small and feature-rich JavaScript library that makes HTML document traversal and manipulation, event handling, animation and Ajax much simpler with an API that works across a wide range of browsers. The official site brings together the download options, the API documentation, release notes, the learning center and the CDN hosting information, and it remains the primary reference for the many sites that still ship jQuery in production.
The most heavily used section is the API documentation, which organizes every method by category such as selectors, traversal, manipulation, CSS, events, effects, Ajax, utilities and deferred objects, with signatures, parameter descriptions, return values and short runnable examples. Release notes and the blog explain what changed between versions, including deprecated interfaces and migration considerations, while the download page lists the compressed and uncompressed builds, slim builds and source maps.
It is particularly useful for developers maintaining long-lived content sites, admin panels, WordPress themes and enterprise intranet pages where jQuery is already part of the stack, for teams planning a gradual migration to native browser APIs or a modern framework, and for beginners reading older tutorials who need to check what a snippet actually does. The CDN index also helps locate a pinned, integrity-checked copy instead of hotlinking an arbitrary mirror.
Compared with modern component frameworks, jQuery does not impose a component model, build step or virtual DOM; it simply wraps DOM operations, which is why it stays approachable for small enhancements but becomes harder to structure as an application grows. Compared with native querySelector and fetch, it normalizes historical browser differences and offers concise chaining, at the cost of an extra dependency. Compared with third-party cheat sheets, the official documentation is versioned and authoritative.
Check the version number before copying any example, because several methods were deprecated or removed in jQuery 3.x and 4.x, and behavior around ready handlers, Ajax and attribute handling has changed over time. Prefer a pinned CDN URL with subresource integrity over an unpinned latest link, load only one copy of the library, and review plugins for maintenance status before adding them. For new projects, consider whether native browser APIs already cover the requirement.