I have been trying to debug an intermittent problem in the WordPress-3.5 uploader, where it seemed a Backbone.js model was getting messed up somewhere. I downloaded the non-minified Backbone.js and Underscore files, pasted them over WordPress’ built-in wp-includes .min.js files, but then it gives a different error than usual.
Is this caused by using a slightly newer .js file from the Backbone and Underscore sites? (I couldn’t find the exact version WordPress uses there), or is there a problem with replacing the .min.js file with the full file? The script was sent to browser, but would not run the same as the builtins.
You should always use same version of Backbone/Underscore files when trying to debug.
Just replace a minified js with a normal js shouldn’t be a problem.
You can download Backbone 0.9.2 and Underscore 1.4.1 from below urls: