JavaScript IntersectionObserver : Object

constructor

Spec

Constructors

new IntersectionObserver(callback : Function, [options : Object]) : IntersectionObserver

callback(entries : Array<IntersectionObserverEntry>, observer : IntersectionObserver) : undefined

options : {

root	Element
rootMargins	String
threshold	Number

}

Example:

<ul></ul>
<script>
// Create an observer to see when item 15 intersects the viewport
const observer = new IntersectionObserver(entries => {
    entries.forEach(e => console.log(e.isIntersecting));
  });

const list = document.querySelector('ul');
for (let i = 0; i < 30; i++) {
  const listItem = document.createElement('li');
  listItem.textContent = 'item ' + i;
  list.appendChild(listItem);

  if (i === 15) {
    observer.observe(listItem);
  }
}
</script>

Run

Results:

Instance Properties

root : Element readonly

rootMargin : String readonly

thresholds : Array<Number> readonly

Instance Methods

disconnect() : undefined

observe(target : Element) : undefined

takeRecords() : Array<IntersectionObserverEntry>

unobserve(target : Element) : undefined

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