I'm trying to build a web application that can send messages to any other tabs the user might have open. I can't figure out if this is even possible, let alone how to do it.
Does anyone have any experience with this postMessage API, for which online resources seem to be rather limited?
By the way, I know this sounds like some sort of awful spam plan, but in fact it's accessibility related-- I'm attempting to use speech-to-text to allow a user to control other web pages. It won't work as an extension because Chrome extensions presently cannot access the mic, at least not in the manner necessary for this idea.