Learn HTTP/networks (including CORS & WebSockets)

HTTP The Hypertext Transfer Protocol (HTTP) is an application protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web. - Wikipedia

CORS Cross-origin resource sharing (CORS) is a mechanism that allows restricted resources (e.g. fonts) on a web page to be requested from another domain outside the domain from which the resource originated. - Wikipedia

WebSockets WebSocket is a protocol providing full-duplex communication channels over a single TCP connection. The WebSocket protocol was standardized by the IETF as RFC 6455 in 2011, and the WebSocket API in Web IDL is being standardized by the W3C. - Wikipedia

HTTP

• HTTP: The Protocol Every Web Developer Must Know - Part 1 [read]
• HTTP: The Protocol Every Web Developer Must Know - Part 2 [read]
• HTTP Fundamentals [watch][$]
• HTTP Succinctly [read]
• High Performance Browser Networking: What every web developer should know about networking and web performance [read]

CORS

• HTTP Status Codes in 60 Seconds [watch]
• HTTP access control (CORS) [read]
• CORS in Action [read][$]

WebSockets

• WebSocket: Lightweight Client-Server Communications [read][$]
• The WebSocket Protocol [read]
• Connect the Web With WebSockets [watch]