Missing Javascript ".map" file for Underscore.js when loading ASP.NET web page [duplicate]

What you're experiencing is source mapping. This allows you to debug with readable code in your browser's developer tools when working with minified JS files.

The minified version of Underscore has this line at the end of the file:

//# sourceMappingURL=underscore-min.map

Your browser's developers tools will try to download underscore-min.map when encountering this line.

If you want to get rid of the error, either:

  1. Remove that line from underscore-min.js
  2. Add underscore-min.map and underscore.js to your project.