$ npm run firefox
> [email protected] firefox /Users/Zac/Desktop/debugger.html
> node bin/firefox-driver --start

/Users/Zac/Desktop/debugger.html/node_modules/selenium-webdriver/lib/promise.js:2291
        throw error;
        ^

WebDriverError: Unable to parse new session response: {"error":"unknown error","message":"Missing 'marionetteProtocol' field in handshake"}
    at WebDriverError (/Users/Zac/Desktop/debugger.html/node_modules/selenium-webdriver/lib/error.js:27:5)
    at doSend.then.response (/Users/Zac/Desktop/debugger.html/node_modules/selenium-webdriver/lib/http.js:335:17)
    at process._tickCallback (internal/process/next_tick.js:103:7)
From: Task: WebDriver.createSession()
    at Function.createSession (/Users/Zac/Desktop/debugger.html/node_modules/selenium-webdriver/lib/webdriver.js:366:24)
    at createGeckoDriver (/Users/Zac/Desktop/debugger.html/node_modules/selenium-webdriver/firefox/index.js:497:27)
    at Driver (/Users/Zac/Desktop/debugger.html/node_modules/selenium-webdriver/firefox/index.js:605:14)
    at start (/Users/Zac/Desktop/debugger.html/bin/firefox-driver.js:42:18)
    at Object.<anonymous> (/Users/Zac/Desktop/debugger.html/bin/firefox-driver.js:47:18)
    at Module._compile (module.js:556:32)
    at Object.Module._extensions..js (module.js:565:10)
    at Module.load (module.js:473:32)
    at tryModuleLoad (module.js:432:12)
    at Function.Module._load (module.js:424:3)
From: Task: WebDriver.navigate().to(http://localhost:7999/todomvc)
    at Driver.schedule (/Users/Zac/Desktop/debugger.html/node_modules/selenium-webdriver/lib/webdriver.js:414:17)
    at Navigation.to (/Users/Zac/Desktop/debugger.html/node_modules/selenium-webdriver/lib/webdriver.js:1042:25)
    at Driver.get (/Users/Zac/Desktop/debugger.html/node_modules/selenium-webdriver/lib/webdriver.js:832:28)
    at Object.<anonymous> (/Users/Zac/Desktop/debugger.html/bin/firefox-driver.js:48:10)
    at Module._compile (module.js:556:32)
    at Object.Module._extensions..js (module.js:565:10)
    at Module.load (module.js:473:32)
    at tryModuleLoad (module.js:432:12)
    at Function.Module._load (module.js:424:3)
    at Module.runMain (module.js:590:10)

npm ERR! Darwin 15.3.0
npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "run" "firefox"
npm ERR! node v6.7.0
npm ERR! npm  v3.10.3
npm ERR! code ELIFECYCLE
npm ERR! [email protected] firefox: `node bin/firefox-driver --start`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the [email protected] firefox script 'node bin/firefox-driver --start'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the debugger.html package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR!     node bin/firefox-driver --start
npm ERR! You can get information on how to open an issue for this project with:
npm ERR!     npm bugs debugger.html
npm ERR! Or if that isn't available, you can get their info via:
npm ERR!     npm owner ls debugger.html
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR!     /Users/Zac/Desktop/debugger.html/npm-debug.log