jQuery UI datepicker customization

I have the jQuery datepicker working, but I need to be able to select more than just dates. I need to be able to select between some strings as well "Yesterday" and "Today" to be precise. So, the underlying input can contain any date as w开发者_JS百科ell as the strings "Yesterday" or "Today".

Is there some way I can do this by tweaking the existing jQuery UI datepicker?

Ultimately, I resorted to just capturing when they click, and if they select Today or Yesterday, putting the word in rather than the actual date.

$('.DatePicker').datepicker({
    showOn: 'button',
    buttonImage: 'images/cal/cal.jpg',
    buttonImageOnly: true,
    changeMonth: true,
    changeYear: true,
    onSelect: function(dateText, inst) {
        var $this = $(this);
        var selected = new Date($this.val());
        var today = new Date();         
        var yesterday = new Date();             
        yesterday.setDate(today.getDate() - 1);

        if (today.toDateString() == selected.toDateString()) {// TODAY
            $this.val('Today');
        } else if (yesterday.toDateString() == selected.toDateString()) {// YESTERDAY
            $this.val('Yesterday');
        }
    }
});

I would have preferred to add a couple buttons to the bottom of the control, but... this will do.