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JavaScript SEO Office Hours Notes: April 8th 2020

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Notes from the Martin Splitt’s JavaScript SEO Office Hours on April 8th 2020


Googlebot Doesn’t Support Web Sockets

Google doesn’t currently have plans to support web sockets when rendering pages, but it may do this if it becomes are more popular technology.


Use Testing Tools to Validate Lazy Loading Images

You can use the Google testing tools to see if Google can see your high quality lazy loading images instead of lower quality placeholder images which may indicate your implementation is not right.


Use User Agent Detection or Interaction Events to Prevent Google Rendering Content

Google will render any content changes triggered by an onload event. You can disable functionality based on the user agent, or change to use an interaction as the trigger to prevent this, and it won’t be considered cloaking.


Slighty Different Content is Not Cloaking

Google is expecting some small differences in content depending on the device, such as a notifications or pop-ups. This this will generally be fine provided the content is generally the same. You should not change content to a different language, and should use a separate URL.


Load Critical CSS as Quickly as Possible

Load your critical CSS as quickly as possible, then only load other CSS later which is non-essential, to prevent pages generating mobile friendly validation errors in Search Console.


Google Testing Tools Won’t Validate 3D and AR Structured Data

Google’s Rich Results and Structured Data Testing Tool won’t validate 3D and Augmented Reality structured data as this is limited to the early access program.


Test Isomorphic Pages with Google’s Testing Tools

Isomorphic websites with either server-side or client-side routing with rehydration are supported by Google. You can use the URL inspection tool, rich results test and mobile-friendly tests to see the rendered HTML visible to Google.


Google May Flatten Iframes into Pages

Google will sometimes flatten an embedded iframe into a page if the iframe is large enough and if . The content is marked as ‘inline’ content but may be treated differently for indexing and ranking. You may see the iframe content inline in Google’s testing tools.


Relevant Hidden Content Will Be Used for Indexing

Google will use any content in the DOM for indexing including hidden content. If the content is invisible but matches the topic of the page, then it may be considered less important than visible text and not show up in snippets, but if the content doesn’t appear to be relevant then it may be excluded.


Structured Data Testing Tool Can’t Test Tag Manager Implementations

The structured data testing tool doesn’t use the latest Google infrastructure and cannot test structured data loaded with Google Tag Manager. The Rich Results test uses the latest Google indexing infrastructure.


Prevent JavaScript Caching for Fresh Content

Google heavily caches JavaScript for rendering, so use versioning to prevent an outdated script blocking new content, such as structured data, from loading.


Structured Data in Static HTML Is More Robust

There is nothing inherently wrong or slower to use JavaScript to deliver structured data, but delivering it in the static HTML is more robust.


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Ruth Everett

Technical SEO

Ruth Everett is a data & insights manager at Code First Girls, and a former technical SEO analyst at Lumar. You'll most often find her helping clients improve their technical SEO, writing about all things SEO, and watching videos of dogs.


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