异步背后的“靠山”就是event loops。 这里的异步准确的说应该叫浏览器的event loops或者说是javaScript运行环境的event loops，因为ECMAScript中没有event loops，event loops是在HTML Standard定义的。

Loops are a fundamental part of JavaScript programming, and understanding how to use them is critical for any developer. For loops, while loops, and do-while loops provide flexibility and control over ...

Despite being single-threaded, JavaScript handles concurrency and asynchronous operations using the event loop. The event loop allows JavaScript to perform non-blocking operations, like handling I/O, ...