CSS & JS Tricks to Optimise UI Performance Without Sacrificing Design
Performance is a constant challenge for web developers. Balancing aesthetics with speed can be tricky, but with smart CSS and JavaScript strategies, you can achieve a sleek, responsive experience without compromising design integrity. Efficient CSS Techniques
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Use CSS Grid and Flexbox Instead of Floats: Modern layout techniques reduce unnecessary calculations and rendering time.
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Minimise Repaints and Reflows: Avoid applying styles that force the browser to recalculate layout positions, such as animating
widthorheight. -
Lazy Load Fonts: Use
font-display: swap;to ensure text is visible while fonts load asynchronously. -
Reduce Overuse of Shadows and Filters: Effects like
box-shadowandblur()can slow performance; use them sparingly. -
Opt for CSS Animations Over JavaScript: Transitions via
transformandopacityare GPU-accelerated, making them smoother.
Optimising JavaScript for Speed
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Debounce and Throttle Events: Prevent excessive function executions, particularly for scrolling and resizing events.
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Avoid Unnecessary DOM Manipulation: Batch updates and use
documentFragmentfor better rendering efficiency. -
Defer or Async JavaScript: Load scripts strategically using
deferorasyncto prevent blocking page rendering. -
Use Efficient Selectors: Target elements precisely, rather than querying large document trees multiple times.
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Reduce Third-Party Script Dependencies: Each external script can introduce delays—only include what's necessary.
Best Practices for a Seamless UI
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Prioritize Above-the-Fold Content: Ensure that primary visuals and text load quickly, improving perceived performance.
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Optimise Images and Icons: Use modern formats like WebP and SVG for lightweight assets.
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Minify and Compress Assets: Reduce CSS and JS file sizes to speed up loading times.
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Leverage Caching: Set appropriate cache policies to minimise redundant downloads.
Applying these techniques will enhance UI responsiveness while maintaining design quality. Users expect fast-loading sites with flawless visuals—these optimisations ensure they get exactly that.
