Identify whether the mouse scroll is scrolling up or down [closed]

I believe the following code can help:

var lastScrollTop = 0;

window.addEventListener('scroll', function (e) {

    // mesma posição
    if (e.scrollY === lastScrollTop) return;

    console.log(this.scrollY < lastScrollTop ? "Cima" :  "Baixo")

    lastScrollTop = this.scrollY;

  }, true)

Basically, I always save the last position of the current scroll. When the previous value is less than the current value of scrollY , it means that I'm rolling up, otherwise down.

this.scrollY always returns the current position scroll of window , starting from 0 , when it is at the top of the page.

It is possible to do this in javascript, with the following script you can identify in console.log :

<script>

var body = document.getElementsByTagName("body")[0];

if (body.addEventListener) {
    // IE9, Chrome, Safari, Opera
    body.addEventListener("mousewheel", detectarDirecaoRolagem, false);
    // Firefox
    body.addEventListener("DOMMouseScroll", detectarDirecaoRolagem, false);
}

function detectarDirecaoRolagem( e )
{
    var delta = null,
        direction = false
    ;
    if ( !e ) {
        e = window.event;
    }
    if ( e.wheelDelta ) { // funciona na maioria dos casos
        delta = e.wheelDelta / 60;
    } else if ( e.detail ) { // funciona no Firefox
        delta = -e.detail / 2;
    }
    if ( delta !== null ) {
        direction = delta > 0 ? 'cima' : 'baixo';
    }

    console.log(direction);

    return direction;
}
</script>