Why Performance Matters
Fast-loading pages improve user satisfaction, SEO ranking, and conversion rates. Even a 100 ms delay can reduce engagement.
Core Principles
- Reduce payload – minify, compress, and serve only needed assets.
- Leverage caching – set proper
Cache‑Controlheaders. - Optimize rendering – avoid layout‑thrashing and large repaint areas.
- Defer non‑critical work – use
async/defer, lazy loading, and web workers.
Live Performance Analyzer
Enter a URL to see a quick performance overview.
Sample Code: Lazy Loading Images
<img src="placeholder.jpg"
data-src="high-res.jpg"
class="lazy">
<script>
const lazyImages = document.querySelectorAll('img.lazy');
const observer = new IntersectionObserver((entries, obs) => {
entries.forEach(entry => {
if(entry.isIntersecting){
const img = entry.target;
img.src = img.dataset.src;
img.classList.remove('lazy');
obs.unobserve(img);
}
});
});
lazyImages.forEach(img => observer.observe(img));
</script>