现代网络开发最佳实践

v20260518

best-practices

本技能提供了全面的现代Web开发最佳实践指南，涵盖安全加固、浏览器兼容性和API使用等方面。它指导用户如何遵循最新的行业标准，进行代码质量审查、安全审计，并提升Web项目的整体健壮性。

Web 开发安全 HTML CSS JavaScript 最佳实践兼容性

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概览

Best practices

Modern web development standards based on Lighthouse best practices audits. Covers security, browser compatibility, and code quality patterns.

Security

HTTPS everywhere

Enforce HTTPS:

<!-- ❌ Mixed content -->
<img src="http://example.com/image.jpg" />
<script src="http://cdn.example.com/script.js"></script>

<!-- ✅ HTTPS only -->
<img src="https://example.com/image.jpg" />
<script src="https://cdn.example.com/script.js"></script>

<!-- ✅ Protocol-relative (will use page's protocol) -->
<img src="//example.com/image.jpg" />

HSTS Header:

Strict-Transport-Security: max-age=31536000; includeSubDomains; preload

Content Security Policy (CSP)

<!-- Basic CSP via meta tag -->
<meta
  http-equiv="Content-Security-Policy"
  content="default-src 'self'; 
               script-src 'self' https://trusted-cdn.com; 
               style-src 'self' 'unsafe-inline';
               img-src 'self' data: https:;
               connect-src 'self' https://api.example.com;"
/>

<!-- Better: HTTP header -->

CSP Header (recommended):

Content-Security-Policy:
  default-src 'self';
  script-src 'self' 'nonce-abc123' https://trusted.com;
  style-src 'self' 'nonce-abc123';
  img-src 'self' data: https:;
  connect-src 'self' https://api.example.com;
  frame-ancestors 'self';
  base-uri 'self';
  form-action 'self';

Using nonces for inline scripts:

<script nonce="abc123">
  // This inline script is allowed
</script>

Security headers

# Prevent clickjacking
X-Frame-Options: DENY

# Prevent MIME type sniffing
X-Content-Type-Options: nosniff

# Enable XSS filter (legacy browsers)
X-XSS-Protection: 1; mode=block

# Control referrer information
Referrer-Policy: strict-origin-when-cross-origin

# Permissions policy (formerly Feature-Policy)
Permissions-Policy: geolocation=(), microphone=(), camera=()

No vulnerable libraries

# Check for vulnerabilities
npm audit
yarn audit

# Auto-fix when possible
npm audit fix

# Check specific package
npm ls lodash

Keep dependencies updated:

// package.json
{
  "scripts": {
    "audit": "npm audit --audit-level=moderate",
    "update": "npm update && npm audit fix"
  }
}

Known vulnerable patterns to avoid:

// ❌ Prototype pollution vulnerable patterns
Object.assign(target, userInput)
_.merge(target, userInput)

// ✅ Safer alternatives
const safeData = JSON.parse(JSON.stringify(userInput))

Input sanitization

// ❌ XSS vulnerable
element.innerHTML = userInput
document.write(userInput)

// ✅ Safe text content
element.textContent = userInput

// ✅ If HTML needed, sanitize
import DOMPurify from 'dompurify'
element.innerHTML = DOMPurify.sanitize(userInput)

Secure cookies

// ❌ Insecure cookie
document.cookie = "session=abc123";

// ✅ Secure cookie (server-side)
Set-Cookie: session=abc123; Secure; HttpOnly; SameSite=Strict; Path=/

Browser compatibility

Doctype declaration

<!-- ❌ Missing or invalid doctype -->
<html lang="en">
  <head>
    <title>Page</title>
  </head>
  <body></body>
</html>

<!-- ✅ HTML5 doctype -->
<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Page</title>
  </head>
  <body></body>
</html>

Character encoding

<!-- ❌ Missing or late charset -->
<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Page</title>
    <meta charset="UTF-8" />
  </head>
  <body></body>
</html>

<!-- ✅ Charset as first element in head -->
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>Page</title>
  </head>
  <body></body>
</html>

Viewport meta tag

<!-- ❌ Missing viewport -->
<head>
  <title>Page</title>
</head>

<!-- ✅ Responsive viewport -->
<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <title>Page</title>
</head>

Feature detection

// ❌ Browser detection (brittle)
if (navigator.userAgent.includes('Chrome')) {
  // Chrome-specific code
}

// ✅ Feature detection
if ('IntersectionObserver' in window) {
  // Use IntersectionObserver
} else {
  // Fallback
}

// ✅ Using @supports in CSS
@supports (display: grid) {
  .container {
    display: grid;
  }
}

@supports not (display: grid) {
  .container {
    display: flex;
  }
}

Polyfills (when needed)

<!-- Load polyfills conditionally -->
<script>
  if (!('fetch' in window)) {
    document.write('<script src="/polyfills/fetch.js"><\/script>')
  }
</script>

<!-- Or use polyfill.io -->
<script src="https://polyfill.io/v3/polyfill.min.js?features=fetch,IntersectionObserver"></script>

Deprecated APIs

Avoid these

// ❌ document.write (blocks parsing)
document.write('<script src="..."></script>');

// ✅ Dynamic script loading
const script = document.createElement('script');
script.src = '...';
document.head.appendChild(script);

// ❌ Synchronous XHR (blocks main thread)
const xhr = new XMLHttpRequest();
xhr.open('GET', url, false); // false = synchronous

// ✅ Async fetch
const response = await fetch(url);

// ❌ Application Cache (deprecated)
<html manifest="cache.manifest">

// ✅ Service Workers
if ('serviceWorker' in navigator) {
  navigator.serviceWorker.register('/sw.js');
}

Event listener passive

// ❌ Non-passive touch/wheel (may block scrolling)
element.addEventListener('touchstart', handler)
element.addEventListener('wheel', handler)

// ✅ Passive listeners (allows smooth scrolling)
element.addEventListener('touchstart', handler, { passive: true })
element.addEventListener('wheel', handler, { passive: true })

// ✅ If you need preventDefault, be explicit
element.addEventListener('touchstart', handler, { passive: false })

Console & errors

No console errors

// ❌ Errors in production
console.log('Debug info') // Remove in production
throw new Error('Unhandled') // Catch all errors

// ✅ Proper error handling
try {
  riskyOperation()
} catch (error) {
  // Log to error tracking service
  errorTracker.captureException(error)
  // Show user-friendly message
  showErrorMessage('Something went wrong. Please try again.')
}

Error boundaries (React)

class ErrorBoundary extends React.Component {
  state = { hasError: false }

  static getDerivedStateFromError(error) {
    return { hasError: true }
  }

  componentDidCatch(error, info) {
    errorTracker.captureException(error, { extra: info })
  }

  render() {
    if (this.state.hasError) {
      return <FallbackUI />
    }
    return this.props.children
  }
}

// Usage
;<ErrorBoundary>
  <App />
</ErrorBoundary>

Global error handler

// Catch unhandled errors
window.addEventListener('error', (event) => {
  errorTracker.captureException(event.error)
})

// Catch unhandled promise rejections
window.addEventListener('unhandledrejection', (event) => {
  errorTracker.captureException(event.reason)
})

Source maps

Production configuration

// ❌ Source maps exposed in production
// webpack.config.js
module.exports = {
  devtool: 'source-map', // Exposes source code
}

// ✅ Hidden source maps (uploaded to error tracker)
module.exports = {
  devtool: 'hidden-source-map',
}

// ✅ Or no source maps in production
module.exports = {
  devtool: process.env.NODE_ENV === 'production' ? false : 'source-map',
}

Performance best practices

Avoid blocking patterns

// ❌ Blocking script
<script src="heavy-library.js"></script>

// ✅ Deferred script
<script defer src="heavy-library.js"></script>

// ❌ Blocking CSS import
@import url('other-styles.css');

// ✅ Link tags (parallel loading)
<link rel="stylesheet" href="styles.css">
<link rel="stylesheet" href="other-styles.css">

Efficient event handlers

// ❌ Handler on every element
items.forEach((item) => {
  item.addEventListener('click', handleClick)
})

// ✅ Event delegation
container.addEventListener('click', (e) => {
  if (e.target.matches('.item')) {
    handleClick(e)
  }
})

Memory management

// ❌ Memory leak (never removed)
const handler = () => {
  /* ... */
}
window.addEventListener('resize', handler)

// ✅ Cleanup when done
const handler = () => {
  /* ... */
}
window.addEventListener('resize', handler)

// Later, when component unmounts:
window.removeEventListener('resize', handler)

// ✅ Using AbortController
const controller = new AbortController()
window.addEventListener('resize', handler, { signal: controller.signal })

// Cleanup:
controller.abort()

Code quality

Valid HTML

<!-- ❌ Invalid HTML -->
<div id="header">
  <div id="header">
    <!-- Duplicate ID -->
  </div>

  <ul>
    <div>Item</div>
    <!-- Invalid child -->
  </ul>

  <a href="/"><button>Click</button></a>
  <!-- Invalid nesting -->
</div>

<!-- ✅ Valid HTML -->
<header id="site-header"></header>

<ul>
  <li>Item</li>
</ul>

<a href="/" class="button">Click</a>

Semantic HTML

<!-- ❌ Non-semantic -->
<div class="header">
  <div class="nav">
    <div class="nav-item">Home</div>
  </div>
</div>
<div class="main">
  <div class="article">
    <div class="title">Headline</div>
  </div>
</div>

<!-- ✅ Semantic HTML5 -->
<header>
  <nav>
    <a href="/">Home</a>
  </nav>
</header>
<main>
  <article>
    <h1>Headline</h1>
  </article>
</main>

Image aspect ratios

<!-- ❌ Distorted images -->
<img src="photo.jpg" width="300" height="100" />
<!-- If actual ratio is 4:3, this squishes the image -->

<!-- ✅ Preserve aspect ratio -->
<img src="photo.jpg" width="300" height="225" />
<!-- Actual 4:3 dimensions -->

<!-- ✅ CSS object-fit for flexibility -->
<img src="photo.jpg" style="width: 300px; height: 200px; object-fit: cover;" />

Permissions & privacy

Request permissions properly

// ❌ Request on page load (bad UX, often denied)
navigator.geolocation.getCurrentPosition(success, error)

// ✅ Request in context, after user action
findNearbyButton.addEventListener('click', async () => {
  // Explain why you need it
  if (await showPermissionExplanation()) {
    navigator.geolocation.getCurrentPosition(success, error)
  }
})

Permissions policy

<!-- Restrict powerful features -->
<meta http-equiv="Permissions-Policy" content="geolocation=(), camera=(), microphone=()" />

<!-- Or allow for specific origins -->
<meta http-equiv="Permissions-Policy" content="geolocation=(self 'https://maps.example.com')" />

Audit checklist

Security (critical)

HTTPS enabled, no mixed content
No vulnerable dependencies (npm audit)
CSP headers configured
Security headers present
No exposed source maps

Compatibility

Valid HTML5 doctype
Charset declared first in head
Viewport meta tag present
No deprecated APIs used
Passive event listeners for scroll/touch

Code quality

No console errors
Valid HTML (no duplicate IDs)
Semantic HTML elements used
Proper error handling
Memory cleanup in components

UX

No intrusive interstitials
Permission requests in context
Clear error messages
Appropriate image aspect ratios

Tools

Tool	Purpose
`npm audit`	Dependency vulnerabilities
SecurityHeaders.com	Header analysis
W3C Validator	HTML validation
Lighthouse	Best practices audit
Observatory	Security scan

References

信息

Category 编程开发

Name best-practices

版本 v20260518

大小 12.48KB

Source tech-leads-club/agent-skills

更新时间 2026-06-13