jQuery Forum

jQuery.expr.filters.inView = function(el) {
    var width = $(el).width(),
        height = $(el).height(),
        offset = $(el).offset(),

        vp_dimensions = {
            height: $(window).height(),
            width: $(window).width()
        },
        y_offset = (document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop),
        x_offset = (document.documentElement.scrollLeft ? document.documentElement.scrollLeft : document.body.scrollLeft);

    return (
    offset.top < (y_offset + vp_dimensions.height) && offset.left < (x_offset + vp_dimensions.width) && (offset.top + height) > y_offset && (offset.left + width) > x_offset);
};$(window).scroll(function() {

    $('li').each(function() {
        var self = $(this),
            title = self.find('img').attr('alt');
        if (self.is(':inView')) {
            $('#title').find('h2').text(title);
        }
    });

}).scroll();