Rendering, JavaScript & Browser Diagnostics

Recipes for inspecting scripts, third-party resources, rendering issues, loaded assets, browser behavior, and DevTools checks.

JavaScriptDevToolsRendering

Recipes

Available recipes

Recipes in this chapter are added over time. Each one includes the business problem, code pattern, explanation, measurement logic, and mistakes to avoid.

Recipe 002

Analyze Canonical Tags to Avoid Search Cannibalization

A JavaScript recipe for checking whether a page points to itself, consolidates into another URL, or sends mixed canonical signals across similar landing pages.

JavaScript Beginner Canonical TagsDuplicate PagesSearch Cannibalization

Recipe 003

Hreflang Alternate Links: Check Multilingual Pages in the Browser

A JavaScript recipe for checking hreflang alternate links, self-reference, x-default, fully qualified URLs, and language-region targeting signals.

JavaScript Beginner HreflangInternational SEOAlternate Links