Best Practices
Learn industry best practices for clean, maintainable code.
HTML Best Practices
Writing semantic, accessible, and maintainable HTML markup is crucial for quality web development.
Use Semantic HTML
Semantic HTML elements provide meaning to content, improving accessibility and SEO.
<!-- Good: Using semantic elements -->
<header>
<nav>
<ul>
<li><a href="/">Home</a></li>
<li><a href="/about">About</a></li>
</ul>
</nav>
</header>
<main>
<article>
<header>
<h1>Article Title</h1>
</header>
<section>
<p>Article content...</p>
</section>
</article>
</main>
<aside>
<h2>Related Articles</h2>
<ul>
<li>...</li>
</ul>
</aside>
<footer>
<p>Copyright information</p>
</footer>Write Accessible HTML
Ensure your content is usable by everyone, including people with disabilities.
<!-- Provide meaningful alt text for images -->
<img src="chart.jpg" alt="Sales increased from $1 million in Q1 to $2 million in Q4">
<!-- Use labels for form inputs -->
<label for="email">Email Address:</label>
<input type="email" id="email" name="email" required>
<!-- Use ARIA attributes when necessary -->
<button aria-label="Close">×</button>
<!-- Ensure proper heading hierarchy -->
<h1>Main Page Title</h1>
<h2>Section Title</h2>
<h3>Subsection Title</h3>Follow Proper Document Structure
Adhere to the standard HTML document structure for consistency.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Page Title</title>
<meta name="description" content="Brief description of the page">
<link rel="stylesheet" href="styles.css">
</head>
<body>
<!-- Content goes here -->
<script src="script.js"></script>
</body>
</html>CSS Best Practices
Writing maintainable, efficient, and reusable CSS code is essential for large projects.
Organize CSS with Methodologies
Use CSS methodologies like BEM (Block Element Modifier) to organize your code.
/* BEM (Block__Element--Modifier) naming convention */
.card { } /* Block */
.card__title { } /* Element */
.card__image { } /* Element */
.card--featured { } /* Modifier */
.card__button--primary { } /* Element modifier */
/* Good: Meaningful names instead of presentational */
.article-list { }
.article-list__item { }
.article-list__title { }
/* Avoid: Presentational names */
.big-blue-button { }
.rounded-corner-box { }Optimize CSS Performance
Efficient CSS improves rendering performance.
/* Good: Efficient selectors */
.nav { }
.nav a { }
.widget { }
/* Avoid: Expensive selectors */
div * .widget { }
table [class*="nav"] > span:before { }
/* Use shorthand properties */
.element {
/* Good: Shorthand */
margin: 10px 20px 10px 20px;
/* Better: More concise shorthand */
margin: 10px 20px;
/* Even better: Different values */
margin: 10px 20px 15px 25px; /* top right bottom left */
}
/* Organize CSS properties in a consistent order */
.component {
/* Positioning */
position: absolute;
top: 0;
right: 0;
/* Box model */
display: block;
width: 100px;
padding: 10px;
border: 1px solid #ccc;
margin: 10px;
/* Typography */
font: normal 16px/1.5 "Helvetica Neue", sans-serif;
color: #333;
/* Visual */
background: #fff;
border-radius: 5px;
}Modular CSS Architecture
Structure your CSS to be modular and reusable.
/* Example folder structure */
css/
├── base/
│ ├── reset.css
│ ├── typography.css
│ └── utilities.css
├── components/
│ ├── buttons.css
│ ├── cards.css
│ └── navigation.css
├── layout/
│ ├── grid.css
│ ├── header.css
│ └── footer.css
└── themes/
└── dark-theme.css
/* Import in main stylesheet */
@import 'base/reset.css';
@import 'base/typography.css';
@import 'components/buttons.css';
@import 'layout/grid.css';Web Accessibility
Making websites accessible to all users, including those with disabilities, is both an ethical and legal requirement.
Color and Contrast
Ensure sufficient contrast between text and background.
/* WCAG guidelines: minimum contrast ratios */
/* Normal text: 4.5:1 ratio */
.high-contrast-text {
color: #212121; /* Dark gray, not pure black */
background-color: #ffffff; /* White background */
}
/* Large text: 3:1 ratio */
.large-text {
color: #757575; /* Medium gray */
font-size: 1.4rem; /* Larger font size */
background-color: #ffffff;
}
/* Focus indicators for keyboard navigation */
.focusable:focus {
outline: 2px solid #4a90e2; /* Blue outline */
outline-offset: 2px;
}Keyboard Navigation
Ensure all interactive elements are accessible via keyboard.
<!-- Make custom elements keyboard accessible -->
<div role="button" tabindex="0" onclick="handleClick()" onkeydown="handleKeyDown(event)">
Custom Button
</div>
/* Style focus indicators appropriately */
[tabindex]:focus,
button:focus,
input:focus,
a:focus {
outline: 2px solid #005fcc;
outline-offset: 2px;
}
/* Skip link for screen reader users */
.skip-link {
position: absolute;
top: -40px;
left: 6px;
color: white;
background: #000;
padding: 8px;
z-index: 1000;
text-decoration: none;
}
.skip-link:focus {
top: 6px;
}Screen Reader Considerations
Provide adequate information for assistive technologies.
<!-- Hidden content for screen readers only -->
.sr-only {
position: absolute;
width: 1px;
height: 1px;
padding: 0;
margin: -1px;
overflow: hidden;
clip: rect(0, 0, 0, 0);
white-space: nowrap;
border: 0;
}
<!-- Use in HTML -->
<img src="chart.jpg" alt="">
<span class="sr-only">Sales increased from $1 million in Q1 to $2 million in Q4</span>
<!-- ARIA live regions for dynamic content -->
<div aria-live="polite" id="status-updates"></div>
<!-- Landmarks for easy navigation -->
<header role="banner">
<nav role="navigation" aria-label="Main navigation">
<main role="main">
<aside role="complementary">
<footer role="contentinfo">Performance Optimization
Optimizing performance enhances user experience and search engine rankings.
CSS Optimization Techniques
Optimize CSS delivery and minimize render-blocking resources.
/* Minimize render-blocking CSS */
<!-- Inline critical CSS in the head -->
<style>
/* Critical above-the-fold CSS */
.header { display: flex; }
.hero { height: 400px; }
</style>
<!-- Load non-critical CSS asynchronously -->
<link rel="preload" href="non-critical.css" as="style" onload="this.onload=null;this.rel='stylesheet'">
/* Minimize CSS file size */
/* Good: Combine similar rules */
.button-primary, .button-secondary {
padding: 10px 15px;
border-radius: 4px;
cursor: pointer;
}
.button-primary { background: #007cba; color: white; }
.button-secondary { background: #eaeaea; color: #333; }
/* Use efficient animations */
/* Good: Use transform and opacity for animations */
.animate-move {
transition: transform 0.3s ease;
}
/* Avoid animating properties that trigger layout/reflow */
.bad-animation {
transition: width 0.3s ease; /* Triggers reflow */
}Image Optimization
Optimize images for faster loading.
<!-- Use appropriate image formats -->
<picture>
<source srcset="image.webp" type="image/webp">
<img src="image.jpg" alt="Description" width="800" height="600">
</picture>
/* Responsive images */
.article-image {
max-width: 100%;
height: auto;
display: block;
}
/* Lazy loading for below-the-fold images */
<img src="placeholder.jpg" data-src="actual-image.jpg" class="lazy-load" alt="Description">Modern CSS Features
Leverage modern CSS features for better performance.
/* CSS Custom Properties (Variables) for maintainability */
:root {
--primary-color: #007cba;
--secondary-color: #6c757d;
--font-size-base: 1rem;
--spacing-unit: 1.5rem;
}
.button {
background: var(--primary-color);
font-size: var(--font-size-base);
margin: var(--spacing-unit);
}
/* CSS Grid and Flexbox for efficient layouts */
.layout {
display: grid;
grid-template-columns: 1fr 3fr;
grid-gap: 1.5rem;
min-height: 100vh;
}
/* Container queries for responsive components (when supported) */
.card {
padding: clamp(1rem, 2.5vw, 2rem);
font-size: clamp(0.8rem, 1.5vw, 1rem);
}