activate_browser.js

#!/usr/bin/osascript -l JavaScript

'use strict'

const Safari = Application("Safari")
const Chrome = Application("Google Chrome")
const Brave = Application("Brave Browser")
const SystemEvents = Application("System Events")
const Firefox = Application("firefox")
const DefaultBrowser = Firefox

// In order of preference
const BROWSERS = [Firefox, Safari, Brave, Chrome]

function run() {
    let processes = SystemEvents.processes

    if (processes.whose({name: {_equals: DefaultBrowser.name()}}).length > 0) {
        DefaultBrowser.activate()
        return
    }

    for (var idx in BROWSERS) {
        let browser = BROWSERS[idx]
        if (processes.whose({name: {_equals: browser.name()}}).length > 0) {
            browser.activate()
            return
        }
    }
}