How to reduce page blocking by optimizing CSS and JavaScript?

When a page loads, CSS and JavaScript may cause loading delays by blocking rendering or parsing. Targeted optimization can effectively reduce blocking and improve page loading performance. CSS Optimization: - Inline critical styles: Extract the CSS necessary for above-the-fold rendering and inline it into the HTML head to avoid external CSS files blocking the rendering path. - Asynchronously load non-critical CSS: For non-above-the-fold styles (such as print styles), use media="print" or rel="preload" tags to prevent them from blocking the main thread. JavaScript Optimization: - Asynchronous/deferred loading: For non-immediately executed JS, use the async (executes immediately after download) or defer (executes after DOM parsing is complete) attributes to avoid blocking HTML parsing. - Code splitting: Use tools (like Webpack) to split JS into small modules, loading only the code required for the current page to reduce the initial loading size. It is recommended to prioritize optimizing above-the-fold critical resources, use tools like Lighthouse to detect blocking resources, and gradually adjust loading strategies to balance performance and functionality, while paying attention to the loading order of core scripts required for user interaction.