Based on the HTTP Network Layer: What Performance Optimizations Can Frontend Developers Implement?

Based on the HTTP network layer, frontend performance optimization primarily focuses on resource loading and transmission efficiency. Here are some performance optimization measures that frontend developers can implement: ### 1. Reduce the Number of HTTP Requests - Merge Files: Combine multiple CSS or JavaScript files into a single file to reduce the number of requests. - Sprite Maps: Merge multiple small icons into a single image and display the required icon using CSS background positioning. - Inline Images (Data URIs): Embed small images directly into HTML or CSS to reduce image requests. ### 2. Use CDN (Content Delivery Network) - Distributed Nodes: CDN caches static resources on multiple global nodes, allowing users to download from nearby servers and reduce latency. - Cache Efficiency: CDN typically optimizes caching to improve the speed of subsequent visits. ### 3. Cache Optimization - Strong Caching: Set HTTP headers like Cache-Control and Expires to cache resources locally on the client until expiration. - Negotiated Caching: Use ETag and Last-Modified to download resources only when updated. ### 4. Lazy Loading and On-Demand Loading - Lazy Loading: Load non-critical resources like images and videos only when scrolled into the viewport. - Code Splitting: Use tools like Webpack to load modules on demand, avoiding unnecessary JavaScript code in single-page applications. ### 5. Optimize Request and Response Headers - Compress Request Headers: Reduce the size and number of cookies and other unnecessary HTTP header information. - Gzip/Brotli Compression: Compress text resources using Gzip or Brotli to reduce transmission size. ### 6. Use of HTTP/2 and HTTP/3 - Multiplexing: HTTP/2 allows parallel transmission of multiple requests/responses over a single connection, eliminating head-of-line blocking. - Server Push: HTTP/2's Server Push can send resources in advance, reducing wait time. - QUIC Protocol: HTTP/3 uses the QUIC protocol to reduce connection establishment time and improve transmission efficiency. ### 7. Optimize TLS/SSL Handshakes - TLS 1.3: Using updated TLS versions reduces round-trip times during handshake. - OCSP Stapling: Servers can provide certificate status instead of clients querying, reducing handshake latency. ### 8. Optimize Resource Loading Order - Critical Requests First: Ensure critical resources (e.g., HTML, CSS, key JavaScript functions) load first. - Asynchronous Loading: Use async and defer attributes to load non-critical JavaScript scripts asynchronously. ### 9. WebP Format - Use WebP: Compared to traditional JPEG or PNG formats, WebP offers smaller file sizes at the same quality level. ### 10. Service Workers - Offline Experience: Service Workers can cache resources and provide access without network connectivity. - Background Sync: Service Workers can synchronize data or push notifications in the background. For example, in a previous project I optimized for an e-commerce website, using lazy loading for images and the WebP format reduced the homepage load time by approximately 30%. Utilizing the multiplexing feature of HTTP/2 significantly improved the parallelism of resource loading, further reducing page load time.