Coder Perfect

jQuery’s causes a 404 error (Not Found)


I’m getting error warnings regarding a missing file called

What is the source of this?

Asked by Paul Irish

Solution #1

The first thing to remember if Chrome DevTools reports a 404 for file (perhaps,, or, but it could be anything), is that this is only requested while using the DevTools. This 404 will not be seen by your users.

You may now either correct it or turn off the sourcemap feature.

After that, it’s a simple remedy. Click the Download the map file link for your version at, and be sure to download the uncompressed file as well.

If you don’t enjoy dealing with variable names like a and c, having the map file in place allows you to debug your minified jQuery using the original sources, which will save you a lot of time and headache.

Here’s where you can learn more about sourcemaps: JavaScript Source Maps: An Overview

Instead of downloading the files, you can disable JavaScript source maps entirely in your settings for the time being. If you never intend to debug JavaScript on this page, this is a good option. Use the cog icon in the bottom right of the DevTools, to open settings, then:

Answered by Paul Irish

Solution #2

By eliminating the line, you may get rid of the 404.


from your jQuery file’s top section

This is how the top of the jQuery file will look.

/*! jQuery v1.10.2 | (c) 2005, 2013 jQuery Foundation, Inc. |

Simply replace it to

/*! jQuery v1.10.2 | (c) 2005, 2013 jQuery Foundation, Inc. | */

It’s a method of reverting an unbuilt state from a combined/minified file. Along with minifying and merging your JavaScript files, you generate a source map that contains information about your original files when you build for production. You can execute a lookup in the source map to get the original place when you query a specific line and column number in your generated JavaScript. Developer tools (currently WebKit nightly versions, Google Chrome, or Firefox 23+) can automatically analyze the source map and make it appear as if you’re running uncombined and unminified files. (You may learn more about this here.)

Answered by kiranvj

Solution #3

The source map comment will be removed, as announced in jQuery 1.11.0/2.1.0 Beta 2 Released, therefore the issue will not appear in future versions of jQuery.

The formal announcement is as follows:

In any case, if you require a source map, it is still available:

More information on the changes may be found here.

Here is assurance that the source-map comment in the minified file has been deleted with the release of jQuery 1.11.0/2.1.0.

Answered by gotqn

Solution #4

Answered by kayz1

Solution #5

This file is required by newer versions of jQuery. describes the file’s usability.


jQuery 1.11.0/2.1.0

/ The compressed file does not include the sourceMappingURL comment.

Answered by Andres Separ

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