У вашего броузера проблема в совместимости с HTML5
Adafruit's ESP8266-based WiFi board is a great tool for building IoT devices. Get blinking and tweeting! Full written tutorial: https://www.hackster.io/glowascii/getting-started-with-the-feather-huzzah-81fe61
* Note: After all that effort, my Maker channel key is still visible at one point, so I've disabled it. Security is tough!