Question

I don’t understand why this doesn’t work. Explanation will be appreciated.

 var scrollTop = $(window).scrollTop();
    var height = $(window).height();
    if (scrollTop === height ) {
        alert("end!");
    }

http://jsfiddle.net/Zasxe/

Answer 1

$(window).height() gives you the size of the user’s viewport, not the size of the total document, which is what you most likely want. To find if the user has reached the end of the document, you’ve got to find the document’s size, by $(document).height().

Furthermore, to find if a user’s reached the end of the document, using jQuery, you need to capture the scroll event, and see if the user’s reached the bottom:

$(window).scroll(function () {
    if ($(window).scrollTop() + $(window).height() === $(document).height()) {
        alert("end!");
    }
});