WebApp dynamic and RT - Best start

Today i was wondering what new can i learn and i challenged myself to develop a full realtime and dynamic web app.

Basically my idea is :

• Acess webpage

• Enter a user and get a response from a webservice(JSON, the service is already done)

  e.g. : I'm receiving a JSON that contains a market cart with fruits prices and quantity

• The aplication in same page, show the return in a list.

  e.g : It'll list single blocks with the fruits,price and quantity

• This list i can remove and add items without calling another page.

  e.g. : I can remove or Add fruits to the basket, and it'll update de total price and quantity

• In the end, it would update this information to the DB

OBS : All this in the same page, in dynamic "Realtime" like in a desktop app.

Well, that doesn't sound hard, i think i could do this way simple with some PHP+HTML+MySQL+AJAX. But i think it'll be a bad written application once there's a lot of easier and more performatic frameworks.

I was searching in web seems that a lot of information like JSP, php frakeworks(zf2,codeigniter),python frameworks(django) etc.. But i would like to receive some suggestions from you guys, what you consider best to start learning.

OBS : I'm already a desktop apps and games developer.

Thank you in advance, i would be thankful if someone can help.