check whether an element is currently visible (JS)

README.md

This is a small Javascript function which tells you whether an HTML element is currently visible - that is, whether or not it's been scrolled out of view on the page.

This function requires jQuery.

isScrolledIntoView.js

function isScrolledIntoView(elem) {
    var docViewTop = $(window).scrollTop();
    var docViewBottom = docViewTop + $(window).height();

    var elemTop = $(elem).offset().top;
    var elemBottom = elemTop + $(elem).height();

    return ( (elemBottom >= docViewTop) && (elemTop <= docViewBottom) && (elemBottom <= docViewBottom) && (elemTop >= docViewTop) );
}