У вашего броузера проблема в совместимости с HTML5
In this tutorial, we shall set up mbed project, we are going to connect ESP with mbed, you may use any mbed enabled board, i'll be using stm32f407 discovery board, if you want to interface ESP with some other microcontroller like PIC18 or Arduino nano etc, I'll also show how to do that, you may follow these mbed tutorials as we shall be using same techniques for interfacing ESP8266 with PIC or other microcontrollers.
Project link: https://github.com/programmer131/esp8266ATServer