Universal Video Speed Adjuster

Adjusts video playback speed with keyboard shortcuts and shows a temporary UI.

Install a Userscript Manager: First, install a browser extension like Violentmonkey (for Firefox) or Tampermonkey (for Chrome).
Create a New Script: Open the extension's dashboard, create a new userscript, and paste the code from the Canvas into the editor.
Adjust Injection Mode: For sites with videos embedded in an iframe, such as Dailymotion, you must change the script's settings. In the extension's dashboard, find the script, go to its settings, and change the injection mode to "content" and run in iframes to on.

Keyboard Shortcuts: Easily adjust video speed with 'Option/Alt + .' (increase) and 'Option/Alt + ,' (decrease) and 'Option/Alt + /' to fastforward
Speed Display: The script shows a temporary, centered box with the current speed, which fades away automatically.
Broad Compatibility: This script is designed to work across many websites and browsers on both Mac and Windows. It is able to adjust video speed even when the video player is in an iframe, a common feature of many video-sharing sites.
Minimalist: No additional UI elements or customizability just a quick and simple script to + - speed by 0.5 and fastforward by 10x