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

Existing Solution

There could be 3 solution from this posting and other answer.

Solution 1

    var lastScrollTop = 0;
    $(window).on('scroll', function() {
        st = $(this).scrollTop();
        if(st < lastScrollTop) {
            console.log('up 1');
        }
        else {
            console.log('down 1');
        }
        lastScrollTop = st;
    });

Solution 2

    $('body').on('DOMMouseScroll', function(e){
        if(e.originalEvent.detail < 0) {
            console.log('up 2');
        }
        else {
            console.log('down 2');
        }
    });

Solution 3

    $('body').on('mousewheel', function(e){
        if(e.originalEvent.wheelDelta > 0) {
            console.log('up 3');
        }
        else {
            console.log('down 3');
        }
    });

---

Multi Browser Test

I couldn't tested it on Safari

chrome 42 (Win 7)

• Solution 1
  • Up : 1 event per 1 scroll
  • Down : 1 event per 1 scroll
• Solution 2
  • Up : Not working
  • Down : Not working
• Solution 3
  • Up : 1 event per 1 scroll
  • Down : 1 event per 1 scroll

Firefox 37 (Win 7)

• Solution 1
  • Up : 20 events per 1 scroll
  • Down : 20 events per 1 scroll
• Solution 2
  • Up : Not working
  • Down : 1 event per 1 scroll
• Solution 3
  • Up : Not working
  • Down : Not working

IE 11 (Win 8)

• Solution 1
  • Up : 10 events per 1 scroll (side effect : down scroll occured at last)
  • Down : 10 events per 1 scroll
• Solution 2
  • Up : Not working
  • Down : Not working
• Solution 3
  • Up : Not working
  • Down : 1 event per 1 scroll

IE 10 (Win 7)

• Solution 1
  • Up : 1 event per 1 scroll
  • Down : 1 event per 1 scroll
• Solution 2
  • Up : Not working
  • Down : Not working
• Solution 3
  • Up : 1 event per 1 scroll
  • Down : 1 event per 1 scroll

IE 9 (Win 7)

• Solution 1
  • Up : 1 event per 1 scroll
  • Down : 1 event per 1 scroll
• Solution 2
  • Up : Not working
  • Down : Not working
• Solution 3
  • Up : 1 event per 1 scroll
  • Down : 1 event per 1 scroll

IE 8 (Win 7)

• Solution 1
  • Up : 2 events per 1 scroll (side effect : down scroll occured at last)
  • Down : 2~4 events per 1 scroll
• Solution 2
  • Up : Not working
  • Down : Not working
• Solution 3
  • Up : 1 event per 1 scroll
  • Down : 1 event per 1 scroll

---

Combined Solution

I checked that side effect from IE 11 and IE 8 is come from if else statement. So, I replaced it with if else if statement as following.

From the multi browser test, I decided to use Solution 3 for common browsers and Solution 1 for firefox and IE 11.

I referred this answer to detect IE 11.

    // Detect IE version
    var iev=0;
    var ieold = (/MSIE (\d+\.\d+);/.test(navigator.userAgent));
    var trident = !!navigator.userAgent.match(/Trident\/7.0/);
    var rv=navigator.userAgent.indexOf("rv:11.0");

    if (ieold) iev=new Number(RegExp.$1);
    if (navigator.appVersion.indexOf("MSIE 10") != -1) iev=10;
    if (trident&&rv!=-1) iev=11;

    // Firefox or IE 11
    if(typeof InstallTrigger !== 'undefined' || iev == 11) {
        var lastScrollTop = 0;
        $(window).on('scroll', function() {
            st = $(this).scrollTop();
            if(st < lastScrollTop) {
                console.log('Up');
            }
            else if(st > lastScrollTop) {
                console.log('Down');
            }
            lastScrollTop = st;
        });
    }
    // Other browsers
    else {
        $('body').on('mousewheel', function(e){
            if(e.originalEvent.wheelDelta > 0) {
                console.log('Up');
            }
            else if(e.originalEvent.wheelDelta < 0) {
                console.log('Down');
            }
        });
    }