问我如何知道一个网页组件是否在屏幕上显示在litelement中？

EN

// 1. Observer options
let options = {
  // The scroll area - mostly body or document
  root: document.querySelector('#parent'),
  rootMargin: '0px',
  threshold: 1.0
};

let callback = () => { /* Do something */ };

// Observe Element
let observer = new IntersectionObserver(callback, options);

// Start observing
const targetElm = document.querySelector('#target');
observer.observe(targetElm);