AMP-JS

AMP-JS is a JavaScript library that powers AMP pages. It's a runtime that orchestrates the optimized loading and rendering of AMP content. To achieve lightning-fast page loads, AMP-JS follows strict web performance best practices.

AMP-HTML restricts the tags you can use so that the exact layout needed to render the page can be known in advance. The AMP-JS runtime calculates page size and converts your custom AMP-HTML tags into HTML that the browser understands. It also assumes control of the loading of resources from the browser, so that it can prioritize resources that are above-the-fold or likely to be viewed by the user.