Web3.js

Web3.js is a robust and flexible collection of TypeScript and JavaScript libraries that allows developers to interact with local or remote Ethereum nodes (or any EVM-compatible blockchain) over HTTP, IPC or WebSocket connections. It is a powerful and efficient toolkit for crafting applications within the Ethereum ecosystem and beyond.

You can learn more about usage at https://docs.web3js.org/

It covers basic and advanced usage with examples, and includes comprehensive API documentation as well as guides for common tasks, like upgrading from older versions.