Readmore.js

Works with existing HTML without complex markup, as the README states: 'you can probably use it with your existing HTML—there's no need for complicated sets of div’s or hardcoded classes.'

Offers numerous options like animation speed, collapsed height, and link text, allowing fine-tuned control over behavior and appearance through JavaScript configuration.

Leverages CSS for animations and responsive design, enabling easy styling with max-height and media queries, as shown in the CSS examples for adaptive layouts.

Provides beforeToggle, afterToggle, and blockProcessed callbacks for advanced interactions, such as scrolling after toggling, demonstrated in the callback example.