Quite a while back, Mike Taylor pointed out that the jQuery CDN has a minified copy of jQuery 1.9.1 with an incorrect map file reference. Basically, it refers to the map for jQuery 1.11.1, and that’s just wrong. If you are trying to debug a site that uses the minified jQuery 1.9.1 file, dev tools will get very confused and make a hard job even harder.
You might think that we could just edit the
https://code.jquery.com/jquery-1.9.1.min.js file to point to the correct map file, which does exist as
A second problem is even more serious. We’ve been advocating that developers use the script’s
The least disruptive option is to remove the
jquery.min.map file that the jQuery 1.9.1 minified file references. It does not affect whether jQuery runs correctly for the visitors of a site. It only has the effect of disabling the source map. Because of these pitfalls of including the
If you need to debug a site using one of these minified files, it is possible to manually associate a map file in Chrome. Open the minified source file, right click over the area of the minified source, and select “Add source map…”.
jquery.min.map file has been removed from the jQuery CDN. We expect that there won’t be any observable change from removing this file, other than restoring sanity to debugging a site that uses jQuery 1.9.1. The jQuery 1.11.1 minified file does not reference its map, so it will continue to work fine and you can associate a map file as mentioned above.
Because caches are so aggressive on CDNs and across the internet, it’s possible that you may still see this map file for a while. If you see some unusual behavior that you think is related to the missing
jquery.min.map file you can open a ticket on the CDN issue tracker.