Hi Anthony,
I believe that you can use a capitalized ‘Space’ in your keylist for a web experiment. In fact, you should be able to use any keys by using this javascript keyboard event viewer: https://w3c.github.io/uievents/tools/key-event-viewer.html
For the key codes to use, look in the “code” column under UI Events.
To make the experiment work both locally in psychoPy and on the web, include both the original psychoPy name and the javascript name. For example, use both ‘space’ and ‘Space’, or both ‘left’ and ‘ArrowLeft’.
Jon Roberts