Enter the rough outline of the URL question (continuously updated)

1.URL analysis （ code ）
2. The query cache （ Cache related knowledge ）
3.DNS analysis （DNS relevant ）
4、 Get IP Address origination HTTP request （ You can ask about all kinds of basic knowledge about the network ,TCP、IP、UDP、HTTPS、HTTP2）
5. establish TCP Three handshakes • If it is HTTPS establish TLS Secure channel connection （HTTPS encryption ）
6. send out HTTP request , This request may go back to the proxy server or the source server .（ Server agent ）
7. Get HTTP Respond to （HTTP Response code ）
8. according to Content-Type To determine the response file type （ Commonly used HTTP The role of the response head ） • stream class , The browser starts the download interface to download files . • text、 Picture class , The browser is displayed directly on the page • html type , The browser will parse the page .
9. • Page parsing • The network process transfers to the rendering process HTML data • Yes HTML Conduct lexical analysis , Build by stack algorithm DOM Trees .（AST Grammar tree ） • If you encounter external resources , The browser will be handed over to the network process to download . • After construction DOM At the same time as the tree , take CSS The code becomes understandable by the browser StyleSheets • Standardize style attribute values （ Company 、 size ） • To calculate the DOM The specific style of each node of the tree • Calculate each DOM The style of the parent nodes of the node （ Style inheritance ） • DOM When the tree is built , Merge StyleSheets build CSSOM Render tree . • Typesetting ： Traverse the rendering tree , Calculate the coordinate position of the element . • layered ： Generate layers for nodes • draw ： Draw page elements one by one with browser instructions .（ How to avoid redrawing and rearranging ） • Gridding • synthesis