How to unsubscribe from all YouTube channels at once

Want to unsubscribe from all of your YouTube channel subscriptions at once?  Here's how.

1. Go to the YouTube subscription manager page.  (If you're not already logged in, you'll need to log in.)

2. Copy the code below and paste it into your browser's address bar.  Some browsers won't paste the javascript: part at the beginning; type it in if it doesn't copy over.

javascript:
(function(){
    var btns = document.getElementsByTagName('button');
    for (var i = 0; i < btns.length; i++) {
        if (btns[i].dataset.isSubscribed == "True") {
            if (!!btns[i].dataset.showUnsubConfirmDialog) {
                delete btns[i].dataset.showUnsubConfirmDialog;
            }
            btns[i].click();
        }
    }
})();

3. Press Enter.

You will be unsubscribed from all channel subscriptions currently displayed on the screen.  No confirmation dialog box will be shown.  (Note that if you have channel subscriptions that are not currently displayed, they won't be removed.)