Core Web Vitals 2026: INP, LCP CLS Optimization

page: window.location.pathname， }; // Use sendBeacon for reliable delivery on page unload if (navigator.sendBeacon) {navigator.sendBeacon(/api/analytics/vitals，value: metric.value，。

rating: metric.rating， needs-improvement，// Attribution data for debugging...(metric.attribution {element: metric.attribution.largestShiftTarget // CLS|| metric.attribution.interactionTarget// INP|| metric.attribution.element，// LCP})。

JSON.stringify(body)); }}// Capture all three Core Web VitalsonCLS(sendToAnalytics);onINP(sendToAnalytics);onLCP(sendToAnalytics); ， onLCP } from web-vitals/attribution;function sendToAnalytics(metric) { const body = {name: metric.name， // Install: npm install web-vitalsimport { onCLS，id: metric.id， poordelta: metric.delta， // good， onINP。