jQuery disable/enable submit button

Question

I have this HTML:

How can I do something li

Answer 1

It will work like this:

$('input[type="email"]').keyup(function() {
    if ($(this).val() != '') {
        $(':button[type="submit"]').prop('disabled', false);
    } else {
        $(':button[type="submit"]').prop('disabled', true);
    }
});

Make sure there is an 'disabled' attribute in your HTML