JavaScript Rendering Check Your page with and without JavaScript compared

The check loads the page once and compares the server's HTML response with the version after JavaScript rendering. For every signal you see both values.

User agent
Some websites respond differently to bots than to browsers. Compare with Chrome if needed.
We store the request with your IP address to run the tool. More in the privacy policy.
How the check works

What is in the server response, and what does JavaScript add?

A browser in searchVIU's rendering cluster loads the page. It records which HTML the server sent and what the page looks like after JavaScript.

Both versions come from the same fetch. So you compare exactly the response the browser received with what it built from it.

The check compares title, meta description, canonical, meta robots, lang attribute, hreflang, structured data, H1 to H6, visible text, images and internal and external links. Open any signal to see what only appears with JavaScript and what is missing with JavaScript. You can also put the full visible text side by side.

The check also tests whether robots.txt blocks the URL for the selected user agent and reports JavaScript redirects.

Why it matters

Google renders JavaScript, other bots don't always

Google runs JavaScript, but in a second step. Bots that only read the source code don't see JavaScript content at all.

Source: Google Search Central, JavaScript SEO basics.

  • Title and canonicalIf JavaScript changes them, a bot without rendering sees different signals.
  • Internal linksA crawler without rendering can't find links that are only created in the browser.
  • TextIf the content only exists in the rendered DOM, the source code stays almost empty.

Frequently asked questions

Why one fetch instead of two?
Many tools fetch the page twice, once without and once with a browser. If the server responds differently to the second fetch or blocks it, you end up comparing two different pages. That's why the check uses the original HTML and the rendered DOM from the same browser fetch.
Which user agent should I choose?
The default is searchVIU Tools. With Chrome you get the page the way a visitor sees it. That helps when a website blocks bots.
Does the check also test blocked resources?
The check shows how many scripts were loaded and whether an error occurred during rendering. Whether robots.txt blocks scripts or CSS is something the robots.txt Tester checks.
Can I check several pages at once?
The check tests one URL per run. For every page of a website, the searchVIU SEO Crawler renders each URL in the weekly crawl.
What do you store from my request?
We store the addresses you entered, the result and your IP address to run the tool. We don't store page content. We also use the checked domain to see which companies are interested in the topic.
Demo

What does your website look like in searchVIU?

After a short call about crawler access and Search Console, Michael shows you searchVIU with your website and a demo project. The demo takes around 30 minutes.

Request a demo