It's a little bit different toggle function, it toggles attribute in HTMLElement and sets value for it

toggleAttribute.js

function toggleAttribute(el, name, value) {
    if(!(el instanceof HTMLElement)) return null;
    if (el.hasAttribute(name)) {
        el.removeAttribute(name);
        return false;
    } else {
        el.setAttribute(name, value != null ? value : "");
        return true;
    }
}