Semrush Website Audit Can Now Render JavaScript
5 min read
Does your website use JavaScript (JS)? It in all probability does like most web sites.
In that case, you should use our Website Audit instrument to uncover extra points than earlier than.
Google renders your webpages’ unloaded JS to see its full content material and to ensure your on-line guests can simply entry all the pieces too. Now, our Website Audit bots render JavaScript in the identical approach to determine any hidden points in your website.
Right here’s how we had been in a position to try this.
What’s New in Website Audit?
We’ve allotted extra sources so we will crawl and render your website’s JavaScript. This implies we will accurately crawl websites largely constructed on JavaScript, even when they’re client-side rendered.
To indicate you the distinction, check out a earlier than and after:
Here is one audit with JS rendering enabled and one other audit (of the identical website) with JS disabled.

See the massive distinction between the variety of errors and warnings earlier than and after? With JS enabled, it could possibly correctly determine the problems that have to be mounted.
How Does JavaScript Impression website positioning and Why Does It Matter?
JavaScript rendering is when a website’s JavaScript information are correctly executed and exhibited to web site guests.
How these information flip from strains of code to an interactive web site in your browser can occur in just a few methods (like client-side vs. server-side rendering). Every has its execs and cons. Nevertheless, websites that use JS and client-side rendering may run into crawling issues, particularly for tech audit bots.
Why does that occur? In brief, it comes right down to sources.
Google has the sources to load each static HTML and injected HTML as soon as a website’s JS is executed. However some website auditing bots don’t have the sources to deal with that job (like ours earlier than this replace).
Right here’s what Airbnb would appear to be to a bot that may’t render JS.

And right here’s what it will appear to be to a bot that may execute and render JavaScript.

What Occurs When Google Renders a Website’s JavaScript?
When Google renders a website’s JavaScript, it first sees if any JS must be executed within the first place. If it does, it goes right into a queue after which will get executed/rendered to disclose the webpage’s full content material. Then, Google indexes it.
Right here’s what that appears like:

Prior to now, we weren’t capable of execute that stage above the place a bot processes the JavaScript and renders it. Now our course of is comparable (minus the indexing).
Why Ought to You Allow JS Crawling in a Website Audit?
You may not see the total image of your website’s points with out enabling JS in your subsequent website crawl.
Enabling JS may provide help to discover related points that had been probably missed earlier than.
Particularly for websites constructed on the app shell mannequin (the place core elements are loaded, however normally not the majority of a website’s content material—consider the sooner Airbnb instance).
Some JavaScript websites could use the app shell mannequin the place the preliminary HTML doesn’t include the precise content material and Google must execute JavaScript earlier than having the ability to see the precise web page content material that JavaScript generates.
How Does Website Audit JavaScript Rendering Work Now?
1. We obtain the preliminary HTML from the net server throughout crawling
2. We load the JS sources which are linked on this HTML
3. Execute and render JS code
4. Wait 5 seconds
5. Website Audit makes use of the ultimate HTML for additional evaluation steps
Once you select to disable JS in Website Audit, we use the unique HTML as we did earlier than.
Does Enabling JS Have an effect on My Limits?
No, it is not going to have an effect on your limits in case you select to allow JS on Website Audit. Nevertheless, solely these with Guru or Enterprise subscriptions can use this function.
Will It Set off Trackers, Advertisements, and Occasion Handlers?
No, Website Audit is not going to set off trackers, adverts, and occasion handlers (i.e. JS triggered by clicking or scrolls). Right here’s what we block when our Website Audit bot crawls a website:
- GA4
- GA3
- Yandex Metrica
- Amplitude
- Adobe Analytics
- Google Advertisements
- OWOX
- SpeedCurve
Does Website Audit Use Chrome for Rendering JS?
Sure, we use the most recent Chromium rendering engine. So, we use the identical know-how as Google does for crawling.
The way to Crawl Your Website’s JS with Website Audit
Crawling your website’s JS with Website Audit is straightforward. First, go to the Website Audit instrument and click on the ‘create challenge’ button.

Subsequent, it’s going to immediate you to arrange the audit. The one distinction is that you just’ll select ‘enabled’ for ‘JS-rendering’ within the crawler settings. You’ll be able to nonetheless depart it disabled in case you’d like or change it later.

You’ll be able to verify in case your audit is rendering your website’s JS by wanting up right here within the report:

The way to Crawl an Current Mission’s JS with Website Audit
If JS rendering isn’t enabled on a present challenge, you’ll be able to change that within the Website Audit settings.

From right here, simply click on the “re-run marketing campaign” button to crawl your website with JS enabled. You’ll be able to disable JS rendering in the identical means if you wish to change it again later.
Discover All Of Your Website’s Points with JS Rendering
JavaScript makes websites extra interactive, dynamic, and personalised. For instance, Netflix makes use of JS to replace the physique of a single internet doc for a speedy, seamless expertise.
Equally, many web sites use the app shell mannequin (in addition to client-side rendering) to learn each the person agent and the location proprietor in their very own methods. Your website could use JS to realize the identical outcomes. And in case your website does, we will determine what points Google could run into with Website Audit’s new JS rendering function.