Yes/no confirmation buttons on a slide-out panel
I would add a couple of named functions:

var hideConfirmationMessage,
    showConfirmationMessage;

hideConfirmationMessage = function () {
    $('.js-confirmation').stop(true).animate({ left : '-100%' }, 500);
};

showConfirmationMessage = function() {  
   $('.js-confirmation').show().stop(true).animate({ left : '0' }, 500);
};


Then your event handler attachment becomes much simpler:

$('.js-confirmation-yes').click(function() {
    hideConfirmationMessage();
    $('.container').delay(500).fadeOut(200).hide(200);
});

$('.js-confirmation-no').click(hideConfirmationMessage);
$('.js-decline-button').click(showConfirmationMessage);


I'm not sure if that's "cleaner" to you but I think it's easier to read and doesn't repeat itself.