Download websites that use jQuery UI

About jQuery UI

Front-end code tends to outlive the people who wrote it. jQuery UI arrived in 2007 as the companion widget set for jQuery, and it answered a real problem of its moment. Dialogs, datepickers, sortable lists, resizable panels and drag and drop all behaved the same way across browsers that agreed on very little else. A site serving jQuery UI today is usually not making a fresh technology decision. The site is carrying forward a theme, an admin screen or a booking form written when the library was the obvious answer, and nobody has had a reason to open that file since.

The distinction matters for how the count should be read. As of September 2026 we see jQuery UI on 2,023,931 sites, a figure that reflects accumulated deployment rather than current enthusiasm. Nothing about the number implies that new projects are choosing it. What the number does describe is a large installed base of code that still runs in visitors' browsers, still ships CSS and JavaScript on every page load, and still belongs to somebody who may not know it is there.

Version data makes the inheritance visible. We record 719 distinct version strings for the library, and the release that appears most often in our data is 1.12.1, which predates the current maintenance arrangement under the OpenJS Foundation. Version detection is inferential and incomplete, because it depends on a readable header comment, a versioned file path or a recognisable build fingerprint. Plenty of installs are concatenated into a single minified bundle and report no version at all, so the version breakdown is a sample of the population rather than a census of it.

Geography behaves the way it does for most long-lived web libraries. United States accounts for 675,189 of the sites where we find it, and the domain mix leans heavily on .com. The concentration is less interesting as a fact than as a filter, since the useful queries almost always start by cutting the population down to a country, a suffix and a co-occurring platform.

The people who buy a list like this are rarely curious about the JavaScript libraries itself. Security teams want to know which suppliers or acquisition targets still expose old client-side code. Agencies selling modernisation work want sites that are demonstrably running a stack assembled long ago, in a form a client will accept as evidence. Vendors of component libraries and low-code builders want the same list for the opposite reason, as a market of sites that already depend on interactive widgets and could be moved. Academic work on dependency decay wants the whole population and its movement between snapshots.

A per-domain lookup answers one question well, which is whether a single site loads the library right now. The downloadable list answers questions a lookup cannot reach. Which hosting providers concentrate these installs, how the library co-occurs with specific content platforms and plugins on the same domain, whether the population is shrinking between snapshots, and how much of it sits behind commercial domains rather than personal ones. The library is MIT licensed and free to use, so presence tells you nothing about spend on its own. Combined with the rest of the technology profile for the same domain, presence becomes a reasonable proxy for the age and the neglect of a front end, and the age of a front end is usually the thing actually being bought.