Which links can a crawler follow?
Crawlers collect <a href> URLs; they don't click elements or run onclick handlers. Link text tells them what the target page is about.
Search engines crawl, render and index pages before they rank them; developers control that with robots rules, canonical URLs, sitemaps, clean URLs, semantic HTML and hreflang for other languages.
Change the code and press Run (Ctrl+Enter). Predict what will happen first, then break it on purpose and read what changes. Your edits are saved and match the lesson page.
Ready for more? This phase has 6 hands-on exercises with automatic checks.
Practice questions
Write the code in the editor, run it, then open the model answer to compare.
Write a robots.txt for a shop that blocks /cart/ and /checkout/ for every crawler and points to its sitemap at https://bagbazaar.example/sitemap.xml.
Write the head tags for the French version of https://bagbazaar.example/fr/sacs on a site with English (/en/bags) and French pages, with English as the fallback.
Write a JavaScript snippet that logs every <a> on the page that has no href.
Explain it without notes
Describe crawling, rendering and indexing, and what can stop each one.
What's the difference between robots.txt and <meta name="robots" content="noindex">?
What is a canonical URL and when do you need one?
How does hreflang work, and what are its common mistakes?
Why is semantic HTML part of SEO?
Preview
Console
Nothing logged yet.Expected console output
Egg-free pancakes: crawlable
Crispy dosa: crawlable
Quick upma: NOT crawlable
Coming soon: NOT crawlable
Click here: crawlable (vague text)
h1 count: 1