Popper.js 1 is the earlier version of the Popper positioning engine that Bootstrap 4 depends on.
11,559 websites in the PageSourceSearch index contain the code that reveals it; the 50 highest-ranked are listed below.
How is Popper.js 1 detected?
The page loads Popper.js 1.x from a CDN path such as popper.js@1. or popper.js/1., which Popper 2 no longer uses. The discovery keyword is the exact bytes PageSourceSearch looks for in every stored page and script:
A literal is matched byte for byte, case-sensitively. Combine it with another keyword, a domain, a kind or a date filter on the search page to narrow the list. About Popper.js 1
Top 50 websites using Popper.js 1
Ranked by the domain's position in the crawl's ranked list (Common Crawl harmonic centrality), highest first. view source opens the stored page or script with the match highlighted. Computed 2026-09-29 20:09:01 UTC.
How does PageSourceSearch know a website uses Popper.js 1?
By the source itself: The page loads Popper.js 1.x from a CDN path such as popper.js@1. or popper.js/1., which Popper 2 no longer uses. PageSourceSearch stores the raw HTML and first-party JavaScript of each crawled site and matches the keyword byte for byte, so every listed site's stored source contains it.
Is this a complete list of websites using Popper.js 1?
No. The page lists the 50 highest-ranked sites in the index whose source holds the keyword, out of 11,559 websites that do; the count is the index's estimate at the time the list was computed. Run the keyword as a search to page through all of them, or add a kind or date filter.
How do I find websites that use Popper.js 1 together with another technology?
Search for both keywords at once: several terms separated by spaces must all be found on the same site, or with the Same page toggle in the same page. For example popper\.js[@/]1\. with wp-content/plugins/ lists the WordPress sites that use Popper.js 1.