Write a program to define an editor, then see what the resulting editor looks like. This can be useful to try things out or to share scripts to explain something or illustrate a bug report.
@lezer packages can be
imported directly by name. Other imports should be URLs. You'll
usually want your script to create an editor
document.body. Press Ctrl-Space to run the current
code, and see the result (boxed in an
<iframe>) in the
“Ouput” tab. When errors occur or things are logged to the console,
you can find them in the “Log” tab.