> Nobody actually does plain “JavaScript” programming for the web anymore, not really anyway. Do they use the core language? Yes. But we no longer use any of the built-in JavaScript->HTML functionality directly.

Which is sort of a shame because there's stuff in there that totally obviates the need to haphazardly traverse the dom with jQuery.

Finding the form an input element belongs to in jQuery:

    $('input').parents('form');

    // or probably
    $('input').parent().parent().parent().find('form');

Finding the same thing using the DOM API:

    document.querySelector('input').form;

You'd want to mix those two, in a real use case:

    $('input').on('click', function(evt) {
        var form = this.form;
    });

Then you don't even need jQuery to use the FormData API:

    // where `submit` uses XHR2 to make a request
    <input type="submit" onclick="submit(this.form)">