Overview
The Critical Rendering Path (CRP) is the process by which a browser receives code and transforms it into a visual representation. Optimizing the CRP is fundamental to improving web performance and ensuring a fast initial load experience.
Key Stages
- DOM Construction: Parsing HTML to build the Document Object Model.
- CSSOM Construction: Parsing CSS to build the CSS Object Model.
- Render Tree: Combining DOM and CSSOM to determine what is visible.
- Layout: Calculating the exact position and size of each element.
- Paint: Filling in the pixels on the screen.
Optimization Strategies
- Minifying Resources: Reducing the size of HTML, CSS, and JS files.
- Eliminating Render-Blocking Resources: Deferring non-critical CSS and JavaScript.
- Optimizing the Order: Loading critical CSS as early as possible.