The URL in question exhibits a meta description that shows discrepancies between the initial server response and the final rendered HTML.
Why is this important?
Although Google's guidelines acknowledge that JavaScript can be used to adjust meta descriptions:
<script>document.querySelector('meta[name="description"]').setAttribute("content", "New Description Set by JS");</script>
It's not necessarily the most search-engine-friendly method to convey webpage metadata.
Rendering pages consumes more resources and time than simply parsing raw HTML content.
Google typically indexes web content in two phases: first, by analyzing the directly fetched HTML, and later by evaluating the rendered page. Only after this second assessment will they refresh their index with the newly rendered content.
It is crucial that the initial HTML contains all essential elements exactly as you intend for them to appear in search indexes, including the meta description.
Should the meta description be modified by JavaScript, it's possible that Google may initially index the HTML response's meta description, which might not reflect the latest updates before the page is rendered and re-assessed.
This is especially critical for webpages with frequently updated content and meta descriptions, as it can lead to a mismatch in Google's indexed version and the current page content.
What does the Optimization check?
This Optimization is triggered whenever there is a discrepancy between the meta descriptions in the server response and the rendered HTML.
Examples that trigger this Optimization
Trigger cases include URLs with meta descriptions that differ between the initial server response and the rendered outcome.
Consider the server response:
<!doctype html><html lang="en"><head> <meta name="description" content="Initial meta description"> <meta name="robots" content="index,follow"> ...</head><body>...</body></html>
And compare it with the rendered HTML:
<!doctype html><html lang="en"><head> <meta name="description" content="Updated meta description after JS execution"> <meta name="robots" content="index,follow"> ...</head><body>...</body></html>
How do you resolve this issue?
Dependence on JavaScript for critical on-page elements like the meta description is generally not recommended due to potential indexing delays or inaccuracies. Also, Google may not render or execute JavaScript effectively in every case.
The meta description is a pivotal element for on-page SEO, and you would want Google's initial crawl to access the correct metadata.
Addressing this problem involves coordinating with the web development team to ensure the meta description remains consistent in the HTML response without being manipulated by JavaScript at render time.