A simple lookup from file name/extension to MIME/media type, generated from mime-db, which in turn is compiled from IANA, Apache and nginx's MIME types.
File Upload widget with multiple file selection, drag&drop support, progress bar, validation and preview images, audio and video for jQuery. Supports cross-domain, chunked and resumable file uploads. Works with any server-side platform (Google App Engine, PHP, Python, Ruby on Rails, Java, etc.) that supports standard HTML form file uploads.
Uses a breadth-first search, when necessary, to resolve the file path using the correct casing, and verify that the file actually exists. Returns consistent results regardless of case sensitivity of the file path and/or operating system.