What is the Chrome browser rendering process?

Browser Rendering Process

Chrome browser's rendering process includes the following steps:

1. Parse HTML: Browser parses HTML document into DOM tree (Document Object Model)
2. Parse CSS: Parses CSS into CSSOM tree (CSS Object Model)
3. Build Render Tree: Merges DOM and CSSOM to create render tree, containing only visible nodes
4. Layout: Calculates position and size of each node in render tree
5. Paint: Draws render tree onto screen
6. Composite: Merges multiple layers for final display on screen

Key Concepts

• DOM Tree: Tree structure representation of HTML elements
• CSSOM Tree: Tree structure representation of CSS styles
• Render Tree: Contains only nodes that need to be displayed with their styles
• Reflow: Recalculates layout when element position or size changes
• Repaint: Redraws when element style changes without affecting layout
• Composite: Uses GPU to merge multiple layers for better performance

Performance Optimization Tips

• Minimize DOM operations to avoid frequent reflows and repaints
• Use CSS3 animations instead of JavaScript animations
• Use transform and opacity properties for animations, which don't trigger reflow
• Use will-change property to hint browser optimization
• Avoid table layouts as they require multiple calculations