The document discusses various ways that web performance can be improved, including reducing the number of server requests, minimizing file sizes through compression and minification, leveraging caching, optimizing browser rendering through techniques like deferred parsing of JavaScript, and using tools to automate optimizations. It emphasizes that most of the end user response time is spent in the frontend and recommends starting performance improvements there.
27. Rendering is parsing render HTML CSS DOM TREE STYLE STRUCT < html > < head > < title >Title</ title > </ head > < body > < div >This is a Text</ div > < div id = "hidden">Hidden</ div > body { padding : 0 ; } #hidden { display : none ; } - document - elem : html - elem : head - elem : title - text : Title - elem : body - elem : div - text : This is a Text - elem : div - attr : id=hidden - text : Hidden - selector : body rule : display : block # default css padding-bottom : 0px # site css padding-left : 0px # site css padding-right : 0px # site css padding-top : 0px # site css - selector : hidden rule : display : none # site css
28. Rendering is layout render DOM TREE STYLE STRUCT - document - elem : html - elem : head - elem : title - text : Title - elem : body - elem : div - text : This is a Text - elem : div - attr : id=hidden - text : Hidden - selector : body rule : display : block # default css padding-bottom : 0px # site css padding-left : 0px # site css padding-right : 0px # site css padding-top : 0px # fsite css - selector : hidden rule : display : none # site css - root - body - block - inline : This is - inline : a Text RENDER TREE reflow
29. Rendering is painting render - root - body - block - inline : This is - inline : a Text RENDER TREE repaint This is a Text
30. Rendering is execution mouse moved mouse pressed mouse released key pressed key released render INPUT OS EVENT QUEUE
31. Execution in one thread mouse moved mouse pressed mouse released key pressed key released render EVENT QUEUE Javascript Execution Native Browser Action
32. Once upon a time ... Few resources Static pages Less javascript
33. Most time on server domain connect send receive render
34. Solution is faster serverside domain connect send receive render