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How to check if a website uses jQuery
By SearchWebCode · Updated November 15, 2026 · jQuery · 2 min read
window.jQuery?.fn?.jquery. A version string identifies the globally exposed copy in that frame. Check loaded scripts when the result is undefined.A jQuery filename in HTML is a clue. A version string from the running page gives you a different observation: the library is exposed in that browser context. Use both checks when documenting a website's JavaScript.
Read the version in the current frame
Open the page, choose Inspect → Console, and evaluate this read-only expression:
window.jQuery?.fn?.jqueryA result such as "4.0.0" comes from jQuery's version property. The expression does not load jQuery or change the page. Use the Console's frame selector if the part you are investigating is inside an iframe.
A result of undefined means that this expression did not find a globally exposed copy in the selected frame. It does not establish that every loaded bundle is free of jQuery.
Confirm the script in Network
- Open Network before reloading the page.
- Filter for
jqueryand inspect matching JavaScript requests. - Read the response or library banner to check what the file contains. A developer can rename a file or give a query parameter an arbitrary version.
- Record the page URL, frame, script URL and observed version. Check again after the interaction that loads the relevant feature.
A failed request is different from a loaded library. Also distinguish an actual script element from a comment, a tutorial example or a connection hint. The page-source search guide explains the browser's different search scopes.
Handle aliases and private copies
The $ name is not exclusive to jQuery. Prefer the explicit jQuery name when checking its version. In jQuery, noConflict() can release the dollar alias; noConflict(true) can release the global jQuery name too, while a page retains its own reference.
Do not call noConflict on a site just to inspect it. It changes globals and may disrupt the page. A bundled copy, a private reference and a different frame are reasons to continue inspecting resources when the simple expression finds nothing.
A controlled example
These local fixtures use the same pinned jQuery 4.0.0 file. They illustrate the limits of the expression; they are not observations about a customer's website.
| Fixture | Top-frame expression | What the check establishes |
|---|---|---|
| Normal script installation | "4.0.0" | A global copy exposes that version. |
Private reference after noConflict(true) | undefined | The private reference still exposes 4.0.0. |
| No jQuery script | undefined | No copy was included in this fixture. |
| jQuery only in an iframe | undefined | The iframe's expression returns 4.0.0. |
Find other websites with a confirmed marker
Once you have confirmed a useful filename or path, search a literal such as jquery.min.js. Inspect the matched source: that query misses versioned filenames and bundled copies, and it can find quoted code. Use the JavaScript library lookup workflow for reviewing a domain list.
The jQuery website report describes stored source references and versioned-filename estimates. Its population is different from the live browser check above. The technology-stack guide shows how to record jQuery alongside other page evidence.
References
See the official jQuery version property, noConflict behavior and Chrome Network reference.
Source counts checked 2026-10-14. They describe stored homepages, not live installations. How the counts are measured.
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Frequently asked questions
Does a missing global mean a website does not use jQuery?
No. The selected frame may not expose a global copy. Inspect loaded resources, private or bundled copies and other frames before drawing a conclusion.
Can a script URL tell me the jQuery version?
It can suggest one. Confirm the file contents or a runtime version property; filenames and version query parameters can be changed independently.