For streaming videos
You need a browser extension for this. After installation, you call it by clicking its "green fast-forward" icon (like the one at upper left on this page) when the video to be edited is showing on your screen. The extension works in
Chrome,
Firefox,
Edge,
and their derivatives.
For local videos
The standalone version of VideoSkip allows you to skip through videos that you have downloaded to your computer, rather than streaming videos.
You can get it from its GitHub repo below, or directly
for a computer or
for a mobile device.
Source code
For those who want to see the code or contribute to its development, it is open-source and can be found at these repos:
The standalone version is just an HTML file and can be executed by simply double-clicking on it. To install the extension you need to unzip the files, and then add the extension as a developer. The process is relatively simple in Chrome, more involved in Firefox.