So I am trying to use the JavaScript on scroll
to call a function. But I wanted to know if I could detect the direction of the the scroll without using jQuery. If not then are there any workarounds?
I was thinking of just putting a 'to top' button but would like to avoid that if I could.
I have now just tried using this code but it didn't work:
if document.body.scrollTop <= 0 {
alert ("scrolling down")
} else {
alert ("scrolling up")
}
It can be detected by storing the previous scrollTop
value and comparing the current scrollTop value with it.
JavaScript :
var lastScrollTop = 0;
// element should be replaced with the actual target element on which you have applied scroll, use window in case of no target element.
element.addEventListener("scroll", function(){ // or window.addEventListener("scroll"....
var st = window.pageYOffset || document.documentElement.scrollTop; // Credits: "https://github.com/qeremy/so/blob/master/so.dom.js#L426"
if (st > lastScrollTop){
// downscroll code
} else {
// upscroll code
}
lastScrollTop = st <= 0 ? 0 : st; // For Mobile or negative scrolling
}, false);