How can I determine the direction of a jQuery scroll event?

Question

I\'m looking for something to this effect:

$(window).scroll(function(event){
   if (/* magic code*/ ){
       // upscroll code
   } else {
      // downscrol         


        

Answer 1

This is an optimal solution for detecting the direction just when the user end scrolling.

var currentScrollTop = 0 ;

$(window).bind('scroll', function () {     

    scrollTop = $(this).scrollTop();

    clearTimeout($.data(this, 'scrollTimer'));
    $.data(this, 'scrollTimer', setTimeout(function() {

        if(scrollTop > currentScrollTop){
            // downscroll code
            $('.mfb-component--bl').addClass('mfbHide');
        }else{
            // upscroll code
            $('.mfb-component--bl').removeClass('mfbHide');
        }
        currentScrollTop = scrollTop;

    }, 250));

});

Answer 2

Why nobody use the event object returned by jQuery on scroll ?

$window.on('scroll', function (event) {
    console.group('Scroll');
    console.info('Scroll event:', event);
    console.info('Position:', this.pageYOffset);
    console.info('Direction:', event.originalEvent.dir); // Here is the direction
    console.groupEnd();
});

I'm using chromium and I didn't checked on other browsers if they have the dir property.

Answer 3

This is simple and easy detection for when the user scrolls away from the top of the page and for when they return to the top.

$(window).scroll(function() {
    if($(window).scrollTop() > 0) {
        // User has scrolled
    } else {
        // User at top of page
    }
});

Answer 4

var tempScrollTop, currentScrollTop = 0; 

$(window).scroll(function(){ 

   currentScrollTop = $("#div").scrollTop(); 

   if (tempScrollTop > currentScrollTop ) {
       // upscroll code
   }
  else if (tempScrollTop < currentScrollTop ){
      // downscroll code
  }

  tempScrollTop = currentScrollTop; 
} 

or use the mousewheel extension, see here.

Answer 5

You can determin mousewhell direction.

$(window).on('mousewheel DOMMouseScroll', function (e) {
    var delta = e.originalEvent.wheelDelta ? 
                   e.originalEvent.wheelDelta : -e.originalEvent.detail;

    if (delta >= 0) {
        console.log('scroll up');
    } else {
        console.log('scroll down');
    }
});

Answer 6

This works in all pc or phones browsers, expanding on the top answers. One can build a more complex event object window["scroll_evt"] then call it in the handleScroll() function. This one triggers for 2 concurrent conditions, if certain delay has elapsed or certain delta is passed to eliminate some unwanted triggers.

window["scroll_evt"]={"delta":0,"delay":0,"direction":0,"time":Date.now(),"pos":$(window).scrollTop(),"min_delta":120,"min_delay":10};
$(window).scroll(function() {

    var currentScroll = $(this).scrollTop();
    var currentTime = Date.now();
    var boolRun=(window["scroll_evt"]["min_delay"]>0)?(Math.abs(currentTime - window["scroll_evt"]["time"])>window["scroll_evt"]["min_delay"]):false;
    boolRun = boolRun && ((window["scroll_evt"]["min_delta"]>0)?(Math.abs(currentScroll - window["scroll_evt"]["pos"])>window["scroll_evt"]["min_delta"]):false);
    if(boolRun){
        window["scroll_evt"]["delta"] = currentScroll - window["scroll_evt"]["pos"];
        window["scroll_evt"]["direction"] = window["scroll_evt"]["delta"]>0?'down':'up';
        window["scroll_evt"]["delay"] =currentTime - window["scroll_evt"]["time"];//in milisecs!!!
        window["scroll_evt"]["pos"] = currentScroll;
        window["scroll_evt"]["time"] = currentTime;
        handleScroll();
    }
});


function handleScroll(){
    event.stopPropagation();
    //alert(window["scroll_evt"]["direction"]);
    console.log(window["scroll_evt"]);
}