add class with JavaScript

Question

I am writing some vanilla JavaScript to create a nice navigation menu. I am stuck on adding an active class.

I am getting elements by class name NOT by id. The belo

Answer 1

document.getElementsByClassName returns a node list. So you'll have to iterate over the list and bind the event to individual elements. Like this...

var buttons = document.getElementsByClassName("navButton");

for(var i = 0; i < buttons.length; ++i){
    buttons[i].onmouseover = function() {
        this.setAttribute("class", "active");
        this.setAttribute("src", "images/arrows/top_o.png");
    }
}