This script is adds some little doodads to your page to help you transcribe local audio files, directly in the browser. It even works within Google Docs. This has only been tested in Google Chrome, and all the instructions are specifically for Chrome; though there's no reason the code itself shouldn't work in other browsers.
Installation is a little fiddly, but doesn't take long.
- Open Chrome Dev Tools. (CTRL + SHIFT + I)
- Go the "Sources" tab.