How you can simple determine the direction of a jQuery scroll event

determine_scroll_direction.js

var scrollDirectionPrevValue = 0;

// Function return:
// true - scroll bottom
// false - scroll top
function scrollDirectionToBottom(scrollTop){
	var directionToBottom = false;
	if( scrollDirectionPrevValue < scrollTop ) directionToBottom = true;
	scrollDirectionPrevValue = scrollTop;
	return directionToBottom;
}

// Addhandler to scroll Events width our func
$(window).on("scroll", function(){
	var scrollTop = $(window).scrollTop();
  console.log( scrollDirectionToBottom(scrollTop) );
})