Check out example codes for "mouse scroll event html". It will help you in understanding the concepts better.
Code Example 1
window.onscroll = function() {myFunction()};
function myFunction() {
if (document.body.scrollTop > 50 || document.documentElement.scrollTop > 50) {
document.getElementById("myP").className = "test";
} else {
document.getElementById("myP").className = "";
}
}
Code Example 2
element.onscroll = function() {
// Code here
}
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