jQuery

"jQuery" combines "j" (JavaScript) and "Query". The idea of "querying the DOM" with CSS selectors is captured directly by the name. Compared to other libraries of the era — Prototype.js, MooTools, and the like — the brevity of jQuery's name expressed its essence in a single word.

To understand why jQuery appeared, you need to picture web development in the early 2000s. Internet Explorer (IE), Netscape / Firefox, Opera, and others each had their own JavaScript implementations, and the same code might or might not work depending on the browser.

Take event listener registration. The standard addEventListener worked in Firefox, while IE 6-8 required a proprietary attachEvent. Even attaching a click event meant writing browser branch code, and it was not unusual for the compatibility shim layer of a single web application to outweigh the application code itself.

In August 2006, a 22-year-old John Resig released jQuery 1.0. He was a student at Rochester Institute of Technology (RIT) at the time. jQuery absorbed all of the per-browser branching internally and gave developers a single API that "did not require thinking about browser differences."

The central idea was selecting elements with CSS selectors. Just writing $('.item') picked out the matching elements, simplifying DOM operations that had previously required document.getElementById or complex tree walks. querySelector itself was standardized after jQuery, so jQuery's idea was effectively imported back into the browser.

The other defining trait was method chaining. Forms like $('.item').addClass('active').fadeIn().on('click', handler) let developers chain operations on a selected set of elements in a DSL-like (Domain Specific Language) flow that influenced how web development itself was written.

jQuery's golden age ran from about 2010 to 2014, when it was reported that around 70 percent of websites used jQuery. Major CMSes such as WordPress and Drupal adopted it as a standard, and Bootstrap (through v4) depended on jQuery as well. For a long stretch of time, "writing JavaScript" effectively meant "writing jQuery."

Since the late 2010s, jQuery's role has gradually shifted. Two big changes account for it.

The first is the maturation of native browser APIs. querySelector, fetch, classList, and addEventListener all became reliably available across major browsers, so plain JavaScript could now express many cases concisely without jQuery.

The second is the rise of React, Vue, and Angular. SPA-style (Single Page Application) development moved away from operating directly on the DOM, embracing instead a "declare state and let the view update automatically" design. That philosophy diverges from jQuery's "manipulate the DOM directly" style, and SPA-era projects tend to choose other frameworks.

Even so, jQuery is still running across an enormous number of websites in active operation. WordPress sites, older e-commerce systems, internal tools, and admin pages of existing services keep jQuery alive in maintenance work, even if new development picks it less often. As a "linguistic partner that shaped the web's history," jQuery remains a fixture in web design textbooks.

jQuery's selectors, DOM manipulation, events, animations, and practical patterns are covered in detail in the jQuery Dictionary.