JavaScript Truly is 100% SEO-Friendly

The SEO Landscape

Prior to 2015, it had been common knowledge in the SEO field that JavaScript (JS) was nearly un-crawlable by Googlebot. At that time, every SEO guru would tell you to strictly use HTML and avoid JavaScript like the plague, since the content wouldn’t be indexed by Googlebot.

However, in 2015 Google announced that JavaScript was actually legible to its crawlers:

“Today, as long as you’re not blocking Googlebot from crawling your JavaScript or CSS files, we are generally able to render and understand your web pages like modern browsers.”
Google, Webmaster Central Blog

At the time, this announcement was a game changer that enriched SEO strategy. But not too long after, companies like Hulu started to uncover holes in Google’s claim of complete compatibility with JS.

The Test

We at Loud Interactive conducted an independent study and found that Googlebot can and does render JavaScript, but only if you follow a specific set of criteria.

Here’s our case study using PowerReviews JavaScript implementation of review content on thousands of websites that instantiates these findings:

PowerReviews is a leading provider in ratings and reviews, Q&A, photo, video and social content collection and display technology. User-generated content and reviews allow shoppers to make confident purchase decisions and provide data and insights that enable brands and retailers to increase sales, understand customer sentiment and the overall customer experience.

The team at PowerReviews build their technology to render collected and displayed reviews and user-generated content with JavaScript. PowerReviews wanted an independent analysis to ensure that the JavaScript review copy on thousands of their client sites was visible and legible to Google search engines.

Loud Interactive conducted an analysis of 95,196 unique URLs from PowerReviews’ client’s sites to test whether the JavaScript rendered review copy is crawled by Googlebot. Through three extensive SEO tests, Loud Interactive found that “the PowerReviews JavaScript review system is 100% compatible with Chrome 41 and, when best practices are applied, does NOT have any rendering or indexing issues within the Google search engine.”

The final analysis proved that PowerReviews, via JavaScript, distributes fully legible, SEO-friendly content to product pages which are crawled and indexed by Googlebot.

Loud Interactive’s analysis of JavaScript’s legibility uncovered critical insights for effective JS implementations. These are the three criteria your JavaScript has to meet for Google to index your URLs:

  1. Script has to render and execute properly in Chrome 41
  2. Script must execute in less than 5 seconds
  3. Script must be error-free

Perhaps Hulu’s switch to JS was unsuccessful because their Script did not meet the above criteria. However, PowerReviews’ standard Javascript implementation fully meets the above criteria.

The Methodology

Below you can find the three tests we conducted to prove the crawlability of PowerReviews review content:

The First Test

First, Loud Interactive performed a test based on a Chrome 41 Selenium WebDriver. The tool took 95,196 of PowerReviews’ JS powered ‘Display 4’ review URLs and rendered them in the Chrome 41-based crawler. Then, it checked for the presence of the PowerReviews CSS classes, indicating the reviews were present in the page’s DOM and could be indexed. The test showed that PowerReviews review content, populated via JS, is properly rendered for Googlebot.

The Second Test

Second, Loud Interactive performed a simple test to validate whether a URL was indexed by Google. This tool uses the Google API and the same export of 95k PowerReviews URLs, appends “info:” to each URL and verifies that Google returns results. URLs that were not included in Google’s index were run through a popular web crawler, Screaming Frog, to determine if the Googlebot search engine crawler encountered 4xx or 5xx errors for reasons not related to JS. If so, these URLs were isolated from URLs that properly rendered and indexed.

The Final Test

Lastly, Loud Interactive checked the Google Index for direct quotes pulled from the review copy. A sample set of PowerReviews URLs with review content and headlines were exported. Using the Google API and a custom built tool, Loud Interactive was able to verify both indexation and rankability of the reviews by comparing the URL list of where the quoted review content was taken and the URLs that ranked within Google for the review content.

Given that the overwhelming majority (98.89%) of these URLs were included in Google indexing and were ranking for a quote from the review copy, we can confidently say that the PowerReviews’ JavaScript implementation is completely SEO-compliant.

Bottom line? JavaScript, when implemented correctly, truly is 100% SEO-friendly!