JavaScript is a programming language used to make websites interactive and dynamic. It can load content after a page opens, update what users see without a full reload, and power features like menus, filters, forms, and single page applications. From an SEO standpoint, JavaScript matters because it can affect how easily search engines access and understand your content, especially if important text or links only appear after scripts run.
The key is making sure critical information is reliably available to both users and crawlers. If search engines cannot render your JavaScript or it takes too long to load, they may miss content, internal links, or metadata, which can hurt indexing and visibility. To keep things clear and accurate, prioritize fast performance, avoid hiding essential content behind user interactions, and consider server side rendering or pre rendering for pages where SEO is important. Testing with tools like Google Search Console’s URL Inspection can also help confirm what Google is actually able to see.