The browser enters the URL address, and what happens to the page rendering

1. DNS Domain name resolution , Get ip Address
2. Browser direction ip Address initiates three handshakes , establish http Connect
3. Successful connection , The server responds to the data required by the client
4. The browser gets the data from the server , Browser parsing DOM Trees ,CSSOM Trees (CSS The rule tree ), Generate render tree , Layout rendering tree , Drawing rendering trees , Browser display page
5. The browser and server waved four times , disconnect

Optimization analysis

• css Put it in head in , Do not load asynchronously css
• js Put it in body At the bottom , Or reasonable use (async defer)
• img Define ahead of time width height