fade element on scroll dow

Question

I'd like to do the fade in the other side : fadeIn from down to up and not like now, fadeOut down to up

 var $elem = $('.test.fade'); for (var i = 0; i <= 5; i++) { $elem.clone().appendTo('body'); } $(window).scroll(function() { $('.fade').each(function() { var bounds = this.getBoundingClientRect(), op = Math.max((bounds.height + Math.min(bounds.top, 0)) / bounds.height, 0); $(this).css('opacity', op); }); }); 

 * { padding: 0; margin: 0; box-sizing: border-box; } .test { height: 70vh; width: 30%; background-color: rgba(0, 0, 0, 0.6); margin: 1em auto; } 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <div class="test fade"></div> 

jsfiddle

Thank you for help.

Answer 1

Change the opacity calculation to this:

op = Math.max((bounds.height - Math.max(bounds.top, 0)) / bounds.height, 0);

So it becomes dependent on the bottom border of the boxes.