Javascript attach an onclick event to all links

Question

I want to attach a function on every link on the site to change a parameter.

How can I do this without jQuery?

How do I traverse every link (it might be a DO

Answer 1

I wanted to offer an improvement on @zatatatata's answer which also works with links with nested elements.

function findLink(el) {
    if (el.tagName == 'A' && el.href) {
        return el.href;
    } else if (el.parentElement) {
        return findLink(el.parentElement);
    } else {
        return null;
    }
};

function callback(e) {
    const link = findLink(e.target);
    if (link == null) { return; }
    e.preventDefault();
    // Do something here
};

document.addEventListener('click', callback, false);

If the clicked element isn't a link, we search its parents to check for a link element.