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11.3 性能监控 ​

关键词: Performance API, 性能指标, 用户体验监控, 性能测试, 性能优化策略, 实时监控, 性能分析, 数据收集

学习目标 ​

  • 掌握Performance API的使用方法
  • 学会监控关键性能指标
  • 了解用户体验监控的实现
  • 掌握性能测试工具的使用
  • 学会制定性能优化策略

11.3.1 Performance API ​

基础Performance API ​

html
<!-- Performance API基础使用 -->
<div class="performance-api-demo">
    <h3>Performance API 监控实例</h3>
    
    <div class="performance-metrics">
        <div class="metric-card">
            <h4>页面加载时间</h4>
            <div class="metric-value" id="load-time">计算中...</div>
        </div>
        
        <div class="metric-card">
            <h4>DOM解析时间</h4>
            <div class="metric-value" id="dom-time">计算中...</div>
        </div>
        
        <div class="metric-card">
            <h4>资源加载时间</h4>
            <div class="metric-value" id="resource-time">计算中...</div>
        </div>
        
        <div class="metric-card">
            <h4>首屏渲染时间</h4>
            <div class="metric-value" id="fcp-time">计算中...</div>
        </div>
    </div>
    
    <div class="performance-details">
        <h4>详细性能数据</h4>
        <div id="performance-details"></div>
    </div>
</div>

<style>
    .performance-api-demo {
        max-width: 1200px;
        margin: 0 auto;
        padding: 20px;
    }
    
    .performance-api-demo h3 {
        text-align: center;
        color: #333;
        margin-bottom: 30px;
    }
    
    .performance-metrics {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
        gap: 20px;
        margin-bottom: 30px;
    }
    
    .metric-card {
        background: white;
        padding: 20px;
        border-radius: 12px;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        text-align: center;
        border-left: 4px solid #3498db;
    }
    
    .metric-card h4 {
        color: #2c3e50;
        margin: 0 0 15px 0;
        font-size: 16px;
    }
    
    .metric-value {
        font-size: 28px;
        font-weight: bold;
        color: #3498db;
    }
    
    .performance-details {
        background: #f8f9fa;
        padding: 20px;
        border-radius: 12px;
    }
    
    .performance-details h4 {
        color: #333;
        margin: 0 0 15px 0;
    }
    
    #performance-details {
        background: #2c3e50;
        color: #ecf0f1;
        padding: 15px;
        border-radius: 8px;
        font-family: monospace;
        font-size: 12px;
        line-height: 1.4;
        white-space: pre-wrap;
        overflow-x: auto;
    }
</style>

<script>
// Performance API 监控实现
class PerformanceMonitor {
    constructor() {
        this.metrics = {};
        this.init();
    }
    
    init() {
        if (document.readyState === 'loading') {
            document.addEventListener('DOMContentLoaded', () => this.measurePerformance());
        } else {
            this.measurePerformance();
        }
        
        window.addEventListener('load', () => this.measureLoadPerformance());
    }
    
    measurePerformance() {
        const timing = performance.timing;
        const navigation = performance.navigation;
        
        // 基础性能指标
        this.metrics = {
            // 页面加载时间
            pageLoadTime: timing.loadEventEnd - timing.navigationStart,
            // DOM解析时间
            domParseTime: timing.domContentLoadedEventEnd - timing.domLoading,
            // 资源加载时间
            resourceLoadTime: timing.loadEventEnd - timing.domContentLoadedEventEnd,
            // 首次内容绘制时间
            firstContentfulPaint: this.getFCP(),
            // 页面类型
            navigationType: navigation.type,
            // 重定向次数
            redirectCount: navigation.redirectCount
        };
        
        this.updateUI();
        this.logPerformanceDetails();
    }
    
    measureLoadPerformance() {
        // 重新计算加载完成后的指标
        const timing = performance.timing;
        
        this.metrics.pageLoadTime = timing.loadEventEnd - timing.navigationStart;
        this.metrics.resourceLoadTime = timing.loadEventEnd - timing.domContentLoadedEventEnd;
        
        this.updateUI();
        this.sendAnalytics();
    }
    
    getFCP() {
        try {
            const paintEntries = performance.getEntriesByType('paint');
            const fcpEntry = paintEntries.find(entry => entry.name === 'first-contentful-paint');
            return fcpEntry ? fcpEntry.startTime : 0;
        } catch (e) {
            return 0;
        }
    }
    
    updateUI() {
        const loadTimeEl = document.getElementById('load-time');
        const domTimeEl = document.getElementById('dom-time');
        const resourceTimeEl = document.getElementById('resource-time');
        const fcpTimeEl = document.getElementById('fcp-time');
        
        if (loadTimeEl) loadTimeEl.textContent = `${this.metrics.pageLoadTime}ms`;
        if (domTimeEl) domTimeEl.textContent = `${this.metrics.domParseTime}ms`;
        if (resourceTimeEl) resourceTimeEl.textContent = `${this.metrics.resourceLoadTime}ms`;
        if (fcpTimeEl) fcpTimeEl.textContent = `${Math.round(this.metrics.firstContentfulPaint)}ms`;
    }
    
    logPerformanceDetails() {
        const detailsEl = document.getElementById('performance-details');
        if (!detailsEl) return;
        
        const details = {
            'Navigation Type': this.getNavigationType(),
            'Page Load Time': `${this.metrics.pageLoadTime}ms`,
            'DOM Parse Time': `${this.metrics.domParseTime}ms`,
            'Resource Load Time': `${this.metrics.resourceLoadTime}ms`,
            'First Contentful Paint': `${Math.round(this.metrics.firstContentfulPaint)}ms`,
            'Redirect Count': this.metrics.redirectCount,
            'Connection Type': this.getConnectionType(),
            'Memory Usage': this.getMemoryInfo()
        };
        
        detailsEl.textContent = JSON.stringify(details, null, 2);
    }
    
    getNavigationType() {
        const types = ['导航', '重新加载', '前进/后退', '未知'];
        return types[this.metrics.navigationType] || '未知';
    }
    
    getConnectionType() {
        return navigator.connection ? 
            `${navigator.connection.effectiveType} (${navigator.connection.downlink}Mbps)` : 
            '未知';
    }
    
    getMemoryInfo() {
        if (performance.memory) {
            return `${Math.round(performance.memory.usedJSHeapSize / 1024 / 1024)}MB`;
        }
        return '不支持';
    }
    
    sendAnalytics() {
        // 发送性能数据到分析服务
        const data = {
            page: window.location.pathname,
            metrics: this.metrics,
            userAgent: navigator.userAgent,
            timestamp: Date.now()
        };
        
        // 使用 sendBeacon 发送数据
        if (navigator.sendBeacon) {
            navigator.sendBeacon('/analytics/performance', JSON.stringify(data));
        } else {
            // 降级方案
            fetch('/analytics/performance', {
                method: 'POST',
                body: JSON.stringify(data),
                headers: { 'Content-Type': 'application/json' }
            }).catch(e => console.log('Analytics send failed:', e));
        }
    }
}

// 初始化性能监控
const performanceMonitor = new PerformanceMonitor();
</script>

高级性能监控 ​

html
<!-- 高级性能监控 -->
<div class="advanced-performance-monitoring">
    <h3>高级性能监控</h3>
    
    <div class="monitoring-features">
        <div class="feature-card">
            <h4>Long Tasks监控</h4>
            <div class="feature-demo">
                <button onclick="simulateLongTask()">模拟长任务</button>
                <div id="long-tasks-info"></div>
            </div>
        </div>
        
        <div class="feature-card">
            <h4>资源监控</h4>
            <div class="feature-demo">
                <button onclick="loadTestResource()">加载测试资源</button>
                <div id="resource-info"></div>
            </div>
        </div>
        
        <div class="feature-card">
            <h4>用户交互监控</h4>
            <div class="feature-demo">
                <button onclick="trackUserInteraction(event)">点击测试</button>
                <div id="interaction-info"></div>
            </div>
        </div>
    </div>
</div>

<style>
    .advanced-performance-monitoring {
        max-width: 1200px;
        margin: 20px auto;
        padding: 20px;
    }
    
    .advanced-performance-monitoring h3 {
        text-align: center;
        color: #333;
        margin-bottom: 30px;
    }
    
    .monitoring-features {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
        gap: 20px;
    }
    
    .feature-card {
        background: white;
        padding: 20px;
        border-radius: 12px;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    }
    
    .feature-card h4 {
        color: #2c3e50;
        margin: 0 0 15px 0;
    }
    
    .feature-demo button {
        background: #3498db;
        color: white;
        border: none;
        padding: 10px 20px;
        border-radius: 6px;
        cursor: pointer;
        margin-bottom: 15px;
    }
    
    .feature-demo button:hover {
        background: #2980b9;
    }
    
    .feature-demo div {
        background: #f8f9fa;
        padding: 10px;
        border-radius: 6px;
        font-size: 14px;
        min-height: 60px;
    }
</style>

<script>
// 高级性能监控功能
class AdvancedPerformanceMonitor {
    constructor() {
        this.longTaskObserver = null;
        this.resourceObserver = null;
        this.interactionMetrics = [];
        this.init();
    }
    
    init() {
        this.setupLongTaskObserver();
        this.setupResourceObserver();
        this.setupInteractionTracking();
    }
    
    setupLongTaskObserver() {
        if ('PerformanceObserver' in window) {
            this.longTaskObserver = new PerformanceObserver((list) => {
                const longTasks = list.getEntries();
                longTasks.forEach(task => {
                    this.handleLongTask(task);
                });
            });
            
            this.longTaskObserver.observe({ entryTypes: ['longtask'] });
        }
    }
    
    setupResourceObserver() {
        if ('PerformanceObserver' in window) {
            this.resourceObserver = new PerformanceObserver((list) => {
                const resources = list.getEntries();
                resources.forEach(resource => {
                    this.handleResourceLoad(resource);
                });
            });
            
            this.resourceObserver.observe({ entryTypes: ['resource'] });
        }
    }
    
    setupInteractionTracking() {
        document.addEventListener('click', (e) => {
            this.trackInteraction('click', e);
        });
        
        document.addEventListener('scroll', (e) => {
            this.trackInteraction('scroll', e);
        });
    }
    
    handleLongTask(task) {
        const info = document.getElementById('long-tasks-info');
        if (info) {
            info.innerHTML = `
                <strong>检测到长任务:</strong><br>
                持续时间: ${task.duration.toFixed(2)}ms<br>
                开始时间: ${task.startTime.toFixed(2)}ms<br>
                类型: ${task.name}
            `;
        }
        
        console.warn('Long task detected:', task);
    }
    
    handleResourceLoad(resource) {
        const info = document.getElementById('resource-info');
        if (info) {
            info.innerHTML = `
                <strong>资源加载:</strong><br>
                名称: ${resource.name.split('/').pop()}<br>
                大小: ${(resource.transferSize / 1024).toFixed(2)}KB<br>
                时间: ${resource.duration.toFixed(2)}ms
            `;
        }
    }
    
    trackInteraction(type, event) {
        const startTime = performance.now();
        
        // 记录交互
        this.interactionMetrics.push({
            type,
            timestamp: startTime,
            target: event.target.tagName
        });
        
        // 更新UI
        const info = document.getElementById('interaction-info');
        if (info) {
            info.innerHTML = `
                <strong>最近交互:</strong><br>
                类型: ${type}<br>
                元素: ${event.target.tagName}<br>
                时间: ${startTime.toFixed(2)}ms
            `;
        }
    }
}

// 全局函数
function simulateLongTask() {
    const start = Date.now();
    while (Date.now() - start < 100) {
        // 模拟长任务
    }
}

function loadTestResource() {
    const img = new Image();
    img.src = `https://picsum.photos/200/200?random=${Math.random()}`;
}

function trackUserInteraction(event) {
    console.log('用户交互已记录');
}

// 初始化高级监控
const advancedMonitor = new AdvancedPerformanceMonitor();
</script>

11.3.2 性能指标监控 ​

核心Web指标 ​

html
<!-- 核心Web指标监控 -->
<div class="core-web-vitals">
    <h3>核心Web指标监控</h3>
    
    <div class="vitals-dashboard">
        <div class="vital-metric">
            <h4>LCP (最大内容绘制)</h4>
            <div class="metric-value" id="lcp-value">测量中...</div>
            <div class="metric-status" id="lcp-status">等待中</div>
        </div>
        
        <div class="vital-metric">
            <h4>FID (首次输入延迟)</h4>
            <div class="metric-value" id="fid-value">等待交互</div>
            <div class="metric-status" id="fid-status">等待中</div>
        </div>
        
        <div class="vital-metric">
            <h4>CLS (累积布局偏移)</h4>
            <div class="metric-value" id="cls-value">测量中...</div>
            <div class="metric-status" id="cls-status">等待中</div>
        </div>
    </div>
    
    <div class="vitals-explanation">
        <h4>指标说明</h4>
        <ul>
            <li><strong>LCP:</strong> 页面主要内容完成渲染的时间（目标: &lt;2.5s）</li>
            <li><strong>FID:</strong> 用户首次交互到浏览器响应的时间（目标: &lt;100ms）</li>
            <li><strong>CLS:</strong> 页面布局稳定性评分（目标: &lt;0.1）</li>
        </ul>
    </div>
</div>

<style>
    .core-web-vitals {
        max-width: 1200px;
        margin: 20px auto;
        padding: 20px;
    }
    
    .core-web-vitals h3 {
        text-align: center;
        color: #333;
        margin-bottom: 30px;
    }
    
    .vitals-dashboard {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        gap: 20px;
        margin-bottom: 30px;
    }
    
    .vital-metric {
        background: white;
        padding: 25px;
        border-radius: 12px;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        text-align: center;
    }
    
    .vital-metric h4 {
        color: #2c3e50;
        margin: 0 0 15px 0;
        font-size: 16px;
    }
    
    .metric-value {
        font-size: 24px;
        font-weight: bold;
        color: #3498db;
        margin-bottom: 10px;
    }
    
    .metric-status {
        padding: 5px 15px;
        border-radius: 20px;
        font-size: 14px;
        color: white;
        background: #95a5a6;
    }
    
    .metric-status.good {
        background: #27ae60;
    }
    
    .metric-status.needs-improvement {
        background: #f39c12;
    }
    
    .metric-status.poor {
        background: #e74c3c;
    }
    
    .vitals-explanation {
        background: #f8f9fa;
        padding: 20px;
        border-radius: 12px;
    }
    
    .vitals-explanation h4 {
        color: #333;
        margin: 0 0 15px 0;
    }
    
    .vitals-explanation ul {
        margin: 0;
        padding-left: 20px;
    }
    
    .vitals-explanation li {
        margin-bottom: 10px;
        line-height: 1.5;
    }
</style>

<script>
// 核心Web指标监控
class CoreWebVitalsMonitor {
    constructor() {
        this.metrics = {
            lcp: 0,
            fid: 0,
            cls: 0
        };
        this.init();
    }
    
    init() {
        this.measureLCP();
        this.measureFID();
        this.measureCLS();
    }
    
    measureLCP() {
        if ('PerformanceObserver' in window) {
            const observer = new PerformanceObserver((list) => {
                const entries = list.getEntries();
                const lastEntry = entries[entries.length - 1];
                
                this.metrics.lcp = lastEntry.startTime;
                this.updateLCPUI();
            });
            
            observer.observe({ entryTypes: ['largest-contentful-paint'] });
        }
    }
    
    measureFID() {
        if ('PerformanceObserver' in window) {
            const observer = new PerformanceObserver((list) => {
                const entries = list.getEntries();
                entries.forEach(entry => {
                    this.metrics.fid = entry.processingStart - entry.startTime;
                    this.updateFIDUI();
                });
            });
            
            observer.observe({ entryTypes: ['first-input'] });
        }
    }
    
    measureCLS() {
        if ('PerformanceObserver' in window) {
            let clsValue = 0;
            
            const observer = new PerformanceObserver((list) => {
                const entries = list.getEntries();
                entries.forEach(entry => {
                    if (!entry.hadRecentInput) {
                        clsValue += entry.value;
                    }
                });
                
                this.metrics.cls = clsValue;
                this.updateCLSUI();
            });
            
            observer.observe({ entryTypes: ['layout-shift'] });
        }
    }
    
    updateLCPUI() {
        const valueEl = document.getElementById('lcp-value');
        const statusEl = document.getElementById('lcp-status');
        
        if (valueEl && statusEl) {
            valueEl.textContent = `${(this.metrics.lcp / 1000).toFixed(2)}s`;
            
            if (this.metrics.lcp <= 2500) {
                statusEl.textContent = '良好';
                statusEl.className = 'metric-status good';
            } else if (this.metrics.lcp <= 4000) {
                statusEl.textContent = '需要改进';
                statusEl.className = 'metric-status needs-improvement';
            } else {
                statusEl.textContent = '较差';
                statusEl.className = 'metric-status poor';
            }
        }
    }
    
    updateFIDUI() {
        const valueEl = document.getElementById('fid-value');
        const statusEl = document.getElementById('fid-status');
        
        if (valueEl && statusEl) {
            valueEl.textContent = `${this.metrics.fid.toFixed(2)}ms`;
            
            if (this.metrics.fid <= 100) {
                statusEl.textContent = '良好';
                statusEl.className = 'metric-status good';
            } else if (this.metrics.fid <= 300) {
                statusEl.textContent = '需要改进';
                statusEl.className = 'metric-status needs-improvement';
            } else {
                statusEl.textContent = '较差';
                statusEl.className = 'metric-status poor';
            }
        }
    }
    
    updateCLSUI() {
        const valueEl = document.getElementById('cls-value');
        const statusEl = document.getElementById('cls-status');
        
        if (valueEl && statusEl) {
            valueEl.textContent = this.metrics.cls.toFixed(3);
            
            if (this.metrics.cls <= 0.1) {
                statusEl.textContent = '良好';
                statusEl.className = 'metric-status good';
            } else if (this.metrics.cls <= 0.25) {
                statusEl.textContent = '需要改进';
                statusEl.className = 'metric-status needs-improvement';
            } else {
                statusEl.textContent = '较差';
                statusEl.className = 'metric-status poor';
            }
        }
    }
}

// 初始化核心Web指标监控
const coreWebVitalsMonitor = new CoreWebVitalsMonitor();
</script>

11.3.3 用户体验监控 ​

用户行为追踪 ​

html
<!-- 用户体验监控 -->
<div class="user-experience-monitoring">
    <h3>用户体验监控</h3>
    
    <div class="ux-metrics">
        <div class="ux-card">
            <h4>页面停留时间</h4>
            <div class="ux-value" id="time-on-page">0秒</div>
        </div>
        
        <div class="ux-card">
            <h4>滚动深度</h4>
            <div class="ux-value" id="scroll-depth">0%</div>
        </div>
        
        <div class="ux-card">
            <h4>点击热图</h4>
            <div class="ux-value" id="click-count">0次点击</div>
        </div>
        
        <div class="ux-card">
            <h4>错误次数</h4>
            <div class="ux-value" id="error-count">0个错误</div>
        </div>
    </div>
</div>

<style>
    .user-experience-monitoring {
        max-width: 1200px;
        margin: 20px auto;
        padding: 20px;
    }
    
    .user-experience-monitoring h3 {
        text-align: center;
        color: #333;
        margin-bottom: 30px;
    }
    
    .ux-metrics {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
        gap: 20px;
    }
    
    .ux-card {
        background: white;
        padding: 20px;
        border-radius: 12px;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        text-align: center;
        border-left: 4px solid #e74c3c;
    }
    
    .ux-card h4 {
        color: #2c3e50;
        margin: 0 0 15px 0;
        font-size: 16px;
    }
    
    .ux-value {
        font-size: 24px;
        font-weight: bold;
        color: #e74c3c;
    }
</style>

<script>
// 用户体验监控
class UserExperienceMonitor {
    constructor() {
        this.startTime = Date.now();
        this.clickCount = 0;
        this.errorCount = 0;
        this.maxScroll = 0;
        this.init();
    }
    
    init() {
        this.trackTimeOnPage();
        this.trackScrollDepth();
        this.trackClicks();
        this.trackErrors();
    }
    
    trackTimeOnPage() {
        setInterval(() => {
            const timeOnPage = Math.floor((Date.now() - this.startTime) / 1000);
            const el = document.getElementById('time-on-page');
            if (el) {
                el.textContent = `${timeOnPage}秒`;
            }
        }, 1000);
    }
    
    trackScrollDepth() {
        window.addEventListener('scroll', () => {
            const scrollTop = window.pageYOffset || document.documentElement.scrollTop;
            const documentHeight = document.documentElement.scrollHeight - window.innerHeight;
            const scrollPercent = Math.round((scrollTop / documentHeight) * 100);
            
            this.maxScroll = Math.max(this.maxScroll, scrollPercent);
            
            const el = document.getElementById('scroll-depth');
            if (el) {
                el.textContent = `${this.maxScroll}%`;
            }
        });
    }
    
    trackClicks() {
        document.addEventListener('click', () => {
            this.clickCount++;
            const el = document.getElementById('click-count');
            if (el) {
                el.textContent = `${this.clickCount}次点击`;
            }
        });
    }
    
    trackErrors() {
        window.addEventListener('error', (event) => {
            this.errorCount++;
            const el = document.getElementById('error-count');
            if (el) {
                el.textContent = `${this.errorCount}个错误`;
            }
            
            // 记录错误详情
            console.error('页面错误:', {
                message: event.message,
                filename: event.filename,
                lineno: event.lineno,
                colno: event.colno,
                error: event.error
            });
        });
    }
}

// 初始化用户体验监控
const uxMonitor = new UserExperienceMonitor();
</script>

11.3.4 性能测试工具 ​

性能测试工具对比 ​

html
<!-- 性能测试工具对比 -->
<div class="performance-testing-tools">
    <h3>性能测试工具对比</h3>
    
    <div class="tools-comparison">
        <div class="tool-card">
            <h4>🚀 Lighthouse</h4>
            <div class="tool-features">
                <ul>
                    <li>Google开发的开源工具</li>
                    <li>支持性能、可访问性、SEO等多项审核</li>
                    <li>提供详细的优化建议</li>
                    <li>可在Chrome DevTools中使用</li>
                </ul>
            </div>
            <div class="tool-usage">
                <h5>使用方法：</h5>
                <pre><code># 命令行使用
npm install -g lighthouse
lighthouse https://example.com --output html --output-path ./report.html

# 编程方式使用
const lighthouse = require('lighthouse');
const chromeLauncher = require('chrome-launcher');

async function runLighthouse() {
    const chrome = await chromeLauncher.launch();
    const result = await lighthouse('https://example.com', {
        port: chrome.port
    });
    await chrome.kill();
    return result;
}</code></pre>
            </div>
        </div>
        
        <div class="tool-card">
            <h4>📊 WebPageTest</h4>
            <div class="tool-features">
                <ul>
                    <li>详细的瀑布图和性能指标</li>
                    <li>支持多地点、多设备测试</li>
                    <li>提供视频录制和截图</li>
                    <li>支持API集成</li>
                </ul>
            </div>
            <div class="tool-usage">
                <h5>API使用：</h5>
                <pre><code>// WebPageTest API
const testUrl = 'https://www.webpagetest.org/runtest.php';
const params = {
    url: 'https://example.com',
    key: 'YOUR_API_KEY',
    location: 'Dulles:Chrome',
    runs: 3,
    fvonly: 1
};

fetch(testUrl, {
    method: 'POST',
    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    body: new URLSearchParams(params)
});</code></pre>
            </div>
        </div>
        
        <div class="tool-card">
            <h4>⚡ GTmetrix</h4>
            <div class="tool-features">
                <ul>
                    <li>结合Lighthouse和WebPageTest</li>
                    <li>提供历史数据追踪</li>
                    <li>支持定期监控</li>
                    <li>详细的优化建议</li>
                </ul>
            </div>
            <div class="tool-usage">
                <h5>API使用：</h5>
                <pre><code>// GTmetrix API
const gtmetrixAPI = 'https://gtmetrix.com/api/2.0/test';
const credentials = btoa('username:api_key');

fetch(gtmetrixAPI, {
    method: 'POST',
    headers: {
        'Authorization': `Basic ${credentials}`,
        'Content-Type': 'application/x-www-form-urlencoded'
    },
    body: 'url=https://example.com'
});</code></pre>
            </div>
        </div>
    </div>
</div>

<style>
    .performance-testing-tools {
        max-width: 1200px;
        margin: 20px auto;
        padding: 20px;
    }
    
    .performance-testing-tools h3 {
        text-align: center;
        color: #333;
        margin-bottom: 30px;
    }
    
    .tools-comparison {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
        gap: 30px;
    }
    
    .tool-card {
        background: white;
        padding: 25px;
        border-radius: 12px;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        border-left: 4px solid #9b59b6;
    }
    
    .tool-card h4 {
        color: #2c3e50;
        margin: 0 0 15px 0;
        font-size: 18px;
    }
    
    .tool-features ul {
        list-style: none;
        padding: 0;
        margin: 0 0 20px 0;
    }
    
    .tool-features li {
        padding: 5px 0;
        color: #666;
        position: relative;
        padding-left: 20px;
    }
    
    .tool-features li::before {
        content: "✓";
        color: #27ae60;
        position: absolute;
        left: 0;
    }
    
    .tool-usage {
        background: #f8f9fa;
        padding: 15px;
        border-radius: 8px;
    }
    
    .tool-usage h5 {
        color: #2c3e50;
        margin: 0 0 10px 0;
    }
    
    .tool-usage pre {
        margin: 0;
        overflow-x: auto;
    }
    
    .tool-usage code {
        background: #2c3e50;
        color: #ecf0f1;
        padding: 10px;
        border-radius: 4px;
        display: block;
        font-size: 10px;
        line-height: 1.4;
    }
</style>

11.3.5 性能优化策略 ​

优化策略制定 ​

html
<!-- 性能优化策略 -->
<div class="performance-optimization-strategy">
    <h3>性能优化策略制定</h3>
    
    <div class="strategy-framework">
        <div class="strategy-step">
            <h4>1. 现状分析</h4>
            <div class="step-content">
                <p>使用工具收集当前性能数据，识别主要瓶颈</p>
                <div class="analysis-checklist">
                    <label><input type="checkbox"> 页面加载时间测试</label>
                    <label><input type="checkbox"> 核心Web指标评估</label>
                    <label><input type="checkbox"> 资源加载分析</label>
                    <label><input type="checkbox"> 用户体验指标</label>
                    <label><input type="checkbox"> 移动端性能测试</label>
                </div>
            </div>
        </div>
        
        <div class="strategy-step">
            <h4>2. 目标设定</h4>
            <div class="step-content">
                <p>基于业务需求设定具体的性能目标</p>
                <div class="target-metrics">
                    <div class="metric-target">
                        <label>页面加载时间目标：</label>
                        <input type="number" placeholder="3" min="1" max="10"> 秒
                    </div>
                    <div class="metric-target">
                        <label>LCP目标：</label>
                        <input type="number" placeholder="2.5" min="1" max="5" step="0.1"> 秒
                    </div>
                    <div class="metric-target">
                        <label>FID目标：</label>
                        <input type="number" placeholder="100" min="50" max="300"> 毫秒
                    </div>
                    <div class="metric-target">
                        <label>CLS目标：</label>
                        <input type="number" placeholder="0.1" min="0" max="0.5" step="0.01">
                    </div>
                </div>
            </div>
        </div>
        
        <div class="strategy-step">
            <h4>3. 优化计划</h4>
            <div class="step-content">
                <p>制定优先级明确的优化计划</p>
                <div class="optimization-priorities">
                    <div class="priority-item high">
                        <h5>高优先级</h5>
                        <ul>
                            <li>关键渲染路径优化</li>
                            <li>图片压缩和格式优化</li>
                            <li>代码分割和懒加载</li>
                        </ul>
                    </div>
                    <div class="priority-item medium">
                        <h5>中优先级</h5>
                        <ul>
                            <li>HTTP/2优化</li>
                            <li>CDN配置</li>
                            <li>缓存策略优化</li>
                        </ul>
                    </div>
                    <div class="priority-item low">
                        <h5>低优先级</h5>
                        <ul>
                            <li>第三方脚本优化</li>
                            <li>字体加载优化</li>
                            <li>细节体验优化</li>
                        </ul>
                    </div>
                </div>
            </div>
        </div>
        
        <div class="strategy-step">
            <h4>4. 实施与监控</h4>
            <div class="step-content">
                <p>执行优化计划并建立持续监控机制</p>
                <div class="monitoring-setup">
                    <div class="monitoring-item">
                        <h5>自动化监控</h5>
                        <p>设置CI/CD流水线中的性能检查</p>
                    </div>
                    <div class="monitoring-item">
                        <h5>定期评估</h5>
                        <p>每月进行性能评估和报告</p>
                    </div>
                    <div class="monitoring-item">
                        <h5>告警机制</h5>
                        <p>设置性能指标异常告警</p>
                    </div>
                </div>
            </div>
        </div>
    </div>
</div>

<style>
    .performance-optimization-strategy {
        max-width: 1200px;
        margin: 20px auto;
        padding: 20px;
    }
    
    .performance-optimization-strategy h3 {
        text-align: center;
        color: #333;
        margin-bottom: 30px;
    }
    
    .strategy-framework {
        display: grid;
        gap: 25px;
    }
    
    .strategy-step {
        background: white;
        padding: 25px;
        border-radius: 12px;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        border-left: 4px solid #3498db;
    }
    
    .strategy-step h4 {
        color: #2c3e50;
        margin: 0 0 15px 0;
        font-size: 18px;
    }
    
    .step-content p {
        color: #666;
        margin-bottom: 15px;
    }
    
    .analysis-checklist {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
        gap: 10px;
    }
    
    .analysis-checklist label {
        display: flex;
        align-items: center;
        gap: 10px;
        color: #333;
        cursor: pointer;
    }
    
    .target-metrics {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
        gap: 15px;
    }
    
    .metric-target {
        display: flex;
        align-items: center;
        gap: 10px;
    }
    
    .metric-target label {
        color: #333;
        font-weight: 500;
    }
    
    .metric-target input {
        padding: 8px;
        border: 1px solid #ddd;
        border-radius: 4px;
        width: 80px;
    }
    
    .optimization-priorities {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        gap: 15px;
    }
    
    .priority-item {
        padding: 15px;
        border-radius: 8px;
        border-left: 4px solid;
    }
    
    .priority-item.high {
        background: #fff5f5;
        border-color: #e74c3c;
    }
    
    .priority-item.medium {
        background: #fff9e6;
        border-color: #f39c12;
    }
    
    .priority-item.low {
        background: #f0f8ff;
        border-color: #3498db;
    }
    
    .priority-item h5 {
        margin: 0 0 10px 0;
        color: #2c3e50;
    }
    
    .priority-item ul {
        margin: 0;
        padding-left: 20px;
    }
    
    .priority-item li {
        margin-bottom: 5px;
        color: #666;
    }
    
    .monitoring-setup {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        gap: 15px;
    }
    
    .monitoring-item {
        background: #f8f9fa;
        padding: 15px;
        border-radius: 8px;
    }
    
    .monitoring-item h5 {
        color: #2c3e50;
        margin: 0 0 10px 0;
    }
    
    .monitoring-item p {
        color: #666;
        margin: 0;
        font-size: 14px;
    }
    
    @media (max-width: 768px) {
        .optimization-priorities {
            grid-template-columns: 1fr;
        }
        
        .monitoring-setup {
            grid-template-columns: 1fr;
        }
    }
</style>

本节要点回顾 ​

  • Performance API：使用浏览器原生API监控页面性能，包括导航时间、资源加载和用户交互
  • 性能指标监控：重点关注LCP、FID、CLS等核心Web指标，建立完整的性能监控体系
  • 用户体验监控：追踪用户行为数据，包括停留时间、滚动深度和交互模式
  • 性能测试工具：掌握Lighthouse、WebPageTest等工具的使用，进行全面性能评估
  • 性能优化策略：建立系统化的优化流程，从分析、目标设定到实施监控的完整闭环

相关学习资源 ​

常见问题FAQ ​

Q: 如何选择合适的性能监控工具？ ​

A: 根据需求选择：开发阶段用Lighthouse进行快速检测；生产环境用RUM（真实用户监控）工具；详细分析用WebPageTest；持续监控用GTmetrix或自建系统。

Q: 核心Web指标的目标值是否适用于所有网站？ ​

A: 核心Web指标提供了通用的性能基准，但具体目标应根据业务特点调整。电商网站可能需要更严格的标准，而内容网站可以适当放宽。

Q: 性能监控数据如何与业务指标关联？ ​

A: 建立性能与业务指标的映射关系，如页面加载时间与转化率、跳出率的关系。通过A/B测试验证性能优化对业务的影响。

Q: 如何处理性能监控中的数据噪声？ ​

A: 使用统计学方法过滤异常数据，关注趋势而非单点数据，按用户群体、设备类型、网络条件等维度分析数据。

Q: 性能监控的频率如何设置？ ​

A: 关键指标实时监控，详细分析定期进行（如每日、每周），重大发布前后加强监控。根据业务重要性和资源情况调整监控频率。

下一节预览：下一节我们将学习移动端优化，重点介绍移动端特殊考虑、触摸事件优化、电池寿命优化、网络使用优化和移动端测试的具体方法。