Check if element is on viewport
#How to use
inViewport(element) it will return true if it is or false if not on viewport.
you can use it on window scroll
$(window).on('scroll', function() { ... });
function inViewport(element) {
var rect = element.getBoundingClientRect();
var html = document.documentElement;
return (
rect.top >= 0 &&
rect.left >= 0 &&
rect.bottom <= (window.innerHeight || html.clientHeight) &&
rect.right <= (window.innerWidth || html.clientWidth)
);
}