javascript getElementsByClassName方法

Posted 2021-05-04

var scrollpos = window.scrollY;
    var headerShip = document.getElementById("header-ship");
    var custLink = document.getElementsByClassName('cust-link');

    function add_class_on_scroll() {
        headerShip.classList.add("hide-h");
      	for(var i = 0; i < custLink.length; i++)
        {
            custLink[i].classList.add("custLinkHide");
        }
    }

    function remove_class_on_scroll() {
        headerShip.classList.remove("hide-h");
      	for(var i = 0; i < custLink.length; i++)
        {
            custLink[i].classList.remove("custLinkHide");
        }
    }

    window.addEventListener('scroll', function(){ 
        //Here you forgot to update the value
        scrollpos = window.scrollY;

        if(scrollpos > 125){
            add_class_on_scroll();
        }
        else {
            remove_class_on_scroll();
        }
        console.log(scrollpos);
    });