Back when I still did web development for a living, I often came across the execCommand() method when
trying to read and write from the clipboard. Now that the Async Clipboard API is basically usable everywhere, we don't
need it anymore. Plus, execCommand() is actually discouraged by the spec itself, and who knows how much longer it will be
supported in browsers.
But, as I was looking into that method again, to document it properly in web-features, I realized it did more than just access the clipboard. It actually supports a bunch of commands meant at making it easy to implement a text editor.
So the following is a test page for the execCommand() to see what works where, over time.