Is bad for SEO if browser need to run synchronous JS to get content?

Question

I'm developing a site using symfony + Vue. The problem is that this HTML with non-standard tags (components) gets into the browser.

All that contained in the <div id="app"> element must process JS to get browser-friendly content with standard tags.

These components would not exist if I used server rendering (SSR), but here I don’t understand a bit: during loading, my page already has all the content needed, no API calls are made to get the content like in SPA.

Is it necessary to use server rendering in this case? Is it bad for SEO that before you get normal content, you need to execute JS code for this.

As far as I know, Google and Bingo index synchronous JavaScript well.

Answer 1

Google doesn't care about the name of the tags in your body section - the crawler renders the site using chrome itself (including synchronous js) so it cares for whatever is printed to the screen. You're safe as long as your tags in the head are standard. It is just safer to have SSR to reduce possible errors (timeouts, things that appear only on interaction, etc..)

But you can check and see what google sees using the google fetch bot: https://www.google.com/webmasters/tools/googlebot-fetch