What are the long-term SEO impacts of implementing JavaScript-heavy websites, and how can SEO professionals ensure proper indexing and ranking?

[Sodocasm]

With the rise of JavaScript-driven websites, how does Googlebot handle content rendered by JavaScript? What techniques can be used to ensure the full content of such websites is indexed properly without sacrificing performance or user experience?

 

[hipcat]

I'm not sure I understand the question properly. JS isn't content itself, it just makes the content do things, mostly effects or actions of some sort.

The majority of my sites rely on some amount of JS usage and I haven't noticed any negative effect at all, as Googlebot crawls your CONTENT, whether good or bad, rather than the delivery of that content.

The only negatives I can think of is if your page loads slow or your content is broken or hidden in some way that the bot can't crawl properly. Then you might have an issue.