Check if an element is in the viewport

The following functions return true if the ele element is visible in the viewport:
const isInViewport = function (ele) {
const rect = ele.getBoundingClientRect();
return (
rect.top >= 0 &&
rect.left >= 0 &&
rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) &&
rect.right <= (window.innerWidth || document.documentElement.clientWidth)
);
};

See also