jQuery Datepicker - 悬停时获取日期

Since you've stated (in comments) that you want the behavior found at kayak.co.in, you can mimic this merely by chaining a mouseenter handler after the .DatePicker call (no change needed to anything else):

$('#date').DatePicker({
    // options...
}).on('mouseenter', '.datepickerDays td:not(.datepickerDisabled, .datepickerNotInMonth)', function (e) { // delegating on the mouseenter event which jQuery patches to be a cross-browser event, and only targeting clickable dates
    var target = $(this).children('a'), // cache lookup
        options = target.parents('.datepicker').data('datepicker'), // get DatePicker options
        current = new Date(options.current), // grab the current month/year
        val = parseInt(target.text(), 10), // grab the target date
        hoverVal = new Date(current.getFullYear(), current.getMonth(), val), // make into an actual date
        hoverDay = hoverVal.getDayName(), // get the short day name
        hoverM = hoverVal.getMonth() + 1, // and month
        hoverD = hoverVal.getDate(), // and date
        hoverText = hoverDay + ' ' + (hoverD < 10 ? '0' + hoverD : hoverD) + '/' + hoverM, // for a formatted text value
        selectedVal = new Date(options.date[0]), // get the selected date (which may just be the initial date without an actual selection or an actual selected date, hereafter "selected")
        selectedDay = selectedVal.getDayName(), // get the short day name
        selectedM = selectedVal.getMonth() + 1, // and month
        selectedD = selectedVal.getDate(), // and date
        selText = selectedDay + ' ' + (selectedD < 10 ? '0' + selectedD : selectedD) + '/' + selectedM, // for a formatted text value
        startDate = $('#startDate').data('lastHovered') || new Date(hoverVal) || selectedVal, // default to: last hovered, current hover, or "selected" date (in that order)
        endDate = $('#endDate').data('lastHovered') || new Date(options.date[1]) || startDate, // default to: last hovered, actual selected date, or "selected" date (in that order)
        startDateSelected = $('#startDate').data('startDateSelected') || $('.datepickerDays .datepickerSelected.first').length > 0, // test whether an actual date was selected
        endDateSelected = !isNaN(options.date[1]) && (options.date[1] - options.date[0] > 86400000), // test whether an end date was selected. end date is set in options when start date is actually selected and is the same day as the selected start date but the time is set to 23:59:59
        selector; // variable to store a selector string
    // no end date has been selectd AND if no start date has been selected, or if it has and the user is hovering over an earlier date, or if the user hasn't selected a date yet
    if (!endDateSelected && (!startDateSelected || (startDateSelected && hoverVal < selectedVal) || hoverVal <= startDate)) {
        selector = '#startDate'; // use the startDate input
        $('#endDate').val(''); // since using startDate, endDate has not been selected. make sure the input is cleared.
    } else if (!endDateSelected){ // otherwise, as long as no end date has been selected
        selector = '#endDate'; // use the endDate input
        $('#startDate').val(selText); // and set the value of startDate back to the actual selected date value
    }
    if (!endDateSelected) { // if the user hasn't picked an end date (which cannot be picked without a start date)
        $(selector).data({ // persist the last hovered date and whether a start date has been selected
            "lastHovered": hoverVal,
            "startDateSelected": startDateSelected // this is necessary as the plugin routinely destroys and recreates the tables that make up the calendars while navigating the calendars
        }).val(hoverText); // set the value of the input to the hovered date
    }
});