Google has recently refined its guidelines for implementing Product markup, aiming to improve the accuracy and effectiveness of shopping results in search. This update provides clearer instructions for webmasters and developers, particularly regarding dynamically-generated markup.

Key Points of the Update:

1. HTML Priority: Google now recommends placing Product markup directly in the initial HTML for optimal results in shopping-related searches.

2. JavaScript-Generated Markup: While still supported, Google advises caution when using JavaScript to generate Product markup, highlighting potential challenges with crawl frequency and reliability.

3. Server Capacity: Websites using JavaScript-generated markup are urged to ensure their servers can handle increased traffic from Google's crawlers.

4. Single Product Focus: Product rich results are now explicitly limited to pages focusing on a single product or its variants, rather than product listings or category pages.

5. Currency-Specific URLs: For products available in multiple currencies, Google recommends using distinct URLs for each currency.

6. Car Product Type: A special note for automotive listings suggests including both Car and Product types in structured data for optimal feature eligibility.

Webmasters and developers should review their current Product markup implementation and consider adjusting their strategies in line with these updated guidelines to ensure optimal performance in Google Search results.

For more detailed information, refer to Google's official documentation on product markup and structured data generation.