jQuery
A DOM manipulation library that predates most modern browser APIs.
LegacybeginnerBeginner-friendlyGuide only -- no course yet
Legacy technology
Not recommended for new projects -- native browser APIs (querySelector, fetch, addEventListener) now cover what jQuery was built to solve. Still essential for maintaining the large amount of existing production code built on it.
Overview
jQuery simplified DOM manipulation, event handling, and AJAX requests at a time when browser APIs were inconsistent across vendors. Modern browsers have since standardized most of what jQuery solved (querySelector, fetch, addEventListener), so new projects rarely add it -- but it remains extremely common in existing production systems, WordPress plugins, and legacy enterprise code.
- What it is
- A JavaScript library wrapping DOM selection, manipulation, and events in a concise API.
- Why it's used
- Historically: to paper over cross-browser inconsistencies. Today: mainly to maintain existing codebases already built on it.
- Where it fits
- You will encounter it maintaining older sites, WordPress themes/plugins, and some enterprise intranets. For new projects, native JavaScript (querySelector, fetch) or a modern framework covers the same ground without the added dependency.
Core concepts
- Selecting elements with $()
- Chaining methods
- Event binding (.on())
- AJAX helpers
Example
The same thing in native JavaScript: document.querySelector('#save-btn').addEventListener('click', () => { ... }) -- jQuery's value was mostly making this shorter and browser-consistent, a gap native JS has since closed.
$("#save-btn").on("click", function () {
$("#status").text("Saved!");
});Common use cases
- Maintaining existing jQuery-based codebases
- WordPress plugin development
Project ideas
- Take a small jQuery snippet and rewrite it using only native DOM APIs, to see the equivalence directly