Intersection Observer

a web page

#one
#two
0.30
0.30
0.60
0.60
0.30
0.30
0.60
0.60
IntersectionObserver is a browser API for detecting when an element enters or leaves some part of the viewport.
You pass some options like rootMargin and threshold, and a callback that will run for each intersection. 
	
		let options = {




	click for more
	  rootMargin: "0px
			0px
			0px
			0px",






	edit
	  threshold: [0.30,0.60]


	}

		

		

	function callback(entries, observer) {

		
  console.log(entries.length) 2
			
  entries.forEach(entry => {
			
    console.log(entry.target.id) #one #two
			
    console.log(entry.isIntersecting)  true false
			
    console.log(entry.intersectionRatio)  0.444 0.000
			
  })
			

		}



		

		

	let observer = new IntersectionObserver(callback, options)

observer.observe(document.querySelector('#one'))
observer.observe(document.querySelector('#two'))

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