切换图标更改

Question

I have toggle and working. Now I want include icon, this not working.

function myFunction(#menu) {
            var add.icon = item.nextElementClass;
            if (o.display === "block") {
                o.display = "none";
            } else {
                o.display = "inline-block";
            }
           }

Answer 1

add() is present on Element.classList property.

Try

icon.classList.add('icon-up-dir');

Answer 2

With native js do simply

 element.classList.toggle('icon-up-dir');

For example toggle