SEO Pulse Quick Tool
See what loads
with JavaScript off
Side-by-side comparison of your page with JavaScript running versus disabled. Word counts, meta tags, and a full source diff — so you know exactly how much of your content depends on JavaScript.
What it does
One click. The full picture.
No interpretation needed.
Click JS Compare from the Quick Tools row and SEO Pulse opens a full-screen overlay split into two views: the page as it normally renders, and the same page with JavaScript disabled. Both load side by side, scroll in sync by default.
Below the views, a stats bar shows word count, image count, link count, and heading count for each side — with the difference highlighted. A meta tag diff table shows the title, description, and canonical value from each version, side by side, with a match, different, or missing status per field.
An auto-detected issues panel calls out anything significant — a JS-only H1, a JS-only canonical, a JS-only schema block — without you needing to scan both panes and spot it yourself.
With JavaScript
Best Running Shoes 2026
★★★★☆ 4.6 (2,318 reviews)
Free shipping over £50
"Customers also bought…"
JavaScript disabled
Best Running Shoes 2026
[missing]
Free shipping over £50
[missing]
Auto-detected issues
Flagged for you — no scanning required
Issues found — 3
H1 only appears with JavaScript enabled
Product schema not present without JavaScript
39% of visible word count depends on JavaScript
Meta tag diff
Title, description, canonical — compared
| Field | JS value | Status |
|---|---|---|
| Title | Best Running Shoes 2026 | ✓ Match |
| Description | Shop our full range... | ⚠ Different |
| Canonical | /shoes/running/ | ✓ Match |
Features
What's included
Side-by-side live view
The page with JavaScript on next to the same page with JavaScript disabled. Scroll sync is on by default so you can compare the same section on both sides at once.
Draggable divider
Drag the centre divider to give more space to either side. Useful when one version has significantly more content to review than the other.
Viewport presets
Switch both views to 375px, 768px, 1024px, or full width with one click — useful for checking whether JavaScript-dependent content behaves differently across breakpoints.
Stats bar
Word count, link count, image count, and heading count shown for both versions side by side, with the gap visible at a glance.
No extra fetches
Meta tag diff table
Title, meta description, and canonical URL compared field by field with a match, different, or missing status — clearer than scanning two full pages by eye.
Auto-detected issues panel
JS-only H1, JS-only canonical, JS-only schema, and the overall content percentage gap are surfaced automatically — you don't have to spot them yourself.
Saves manual review
Line-by-line source diff
A full comparison of the raw server HTML against the rendered DOM, line by line — for when you need to see the actual markup difference, not just a content summary.
Light and dark theme
Toggle the tool's own theme independently of your browser or OS setting — useful when comparing against a light-themed page.
Export as HTML report
Generate a standalone report summarising the differences found — word counts, meta diff, flagged issues — ready to share with a developer or client.
Worth knowing: the "JavaScript disabled" view is a sandboxed approximation of an HTML-only crawl — not an exact simulation of any specific search engine crawler. It's a strong, accurate signal for what content depends on JavaScript to render, which is what matters for identifying potential SEO risk. We label it honestly as "JS disabled" rather than claiming it replicates Googlebot exactly, because it doesn't — and we'd rather you trust the labels than chase a number that overstates what we can verify.
Why it matters
JavaScript-dependent content
is a real, common risk
Search engines don't always execute JavaScript on every crawl pass. Content that only exists after JavaScript runs may be missed entirely on a first-pass HTML crawl — and you'd have no way to know without checking.
Product details client-rendered
Price, availability, and review counts loaded via JavaScript after the initial page load are common on e-commerce sites built with React or Vue storefronts.
Schema injected by tag managers
Structured data added via Google Tag Manager only exists in the rendered DOM — it's invisible to a raw HTML fetch, which is exactly what JS Compare reveals.
Headline or H1 set by client-side JS
Some single-page apps render the page shell server-side but populate the main heading and body content with JavaScript after hydration.
FAQ
Common questions
What is JS Compare in SEO Pulse? +
JS Compare is a side-by-side tool that shows the page with JavaScript running normally next to a version with JavaScript disabled. It highlights what content, headings, links, and metadata only appear when JavaScript runs — useful for identifying content that may not be present in a raw, first-pass HTML crawl.
Does JS Compare show exactly what Googlebot sees? +
Not exactly, and we don't claim it does. The no-JavaScript side uses a sandboxed view with scripts disabled, which approximates an HTML-only crawl but isn't a perfect simulation of any specific crawler's behaviour. It's a strong directional signal for what content depends on JavaScript to render — not a guarantee of how any particular bot will process the page.
What does the word count comparison tell me? +
It shows the visible word count with JavaScript on versus off, so you can see how much of your page's content depends on client-side rendering. A large gap between the two numbers suggests a meaningful portion of your content may not be present in the raw HTML that some crawlers process first.
What's the difference between the stats bar and the source diff? +
The stats bar gives you quick counts — words, links, images, headings — for a fast read on the scale of the difference. The line-by-line source diff goes deeper, comparing the actual raw HTML markup against the rendered DOM, useful when you need to see exactly which lines of code differ rather than just a summary count.
Can I export the JS Compare results? +
Yes. JS Compare includes an export option that generates a standalone HTML report summarising the word count differences, meta tag diff, and flagged issues — so you can share findings with a developer or client without them needing to install the extension.
Why does my page show a JS-only H1 or canonical? +
This means that signal only appears once JavaScript has run — it's not present in the raw HTML returned by the server. This is common on React, Next.js, and Nuxt sites where content is hydrated client-side, and on pages where schema or metadata is injected via a tag manager. It's worth investigating because crawlers on a first-pass HTML-only crawl may not see that signal.
Compare any page in one click
Install SEO Pulse, open a page, click JS Compare in Quick Tools.
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