Answers for "jquery detect div visible from another page"

how to detect a section is visible in jquery

$.fn.isInViewport = function() {var elementTop = $(this).offset().top;var elementBottom = elementTop + $(this).outerHeight();var viewportTop = $(window).scrollTop();var viewportBottom = viewportTop + $(window).height();return elementBottom > viewportTop && elementTop < viewportBottom;};