通过html表单将两个JQuery Datepicker变量传递给PHP变量

我有一个JQuery Datepicker修改为根据用户选择的日期选择周范围，并提交一个名为"weekDate"的HTML表单onSelect:

$(document).ready(function()
{  
    var startDate;
    var endDate;
    var selectCurrentWeek = function() {
        window.setTimeout(function () {
            $('.week-picker').find('.ui-datepicker-current-day a').addClass('ui-state-active')
        }, 1);
    }
    $('.week-picker').datepicker( {
        showOtherMonths: true,
        selectOtherMonths: true,
        onSelect: function(dateText, inst) { 
            var date = $(this).datepicker('getDate');
            startDate = new Date(date.getFullYear(), date.getMonth(), date.getDate() - date.getDay());
            endDate = new Date(date.getFullYear(), date.getMonth(), date.getDate() - date.getDay() + 6);
            var dateFormat = inst.settings.dateFormat || $.datepicker._defaults.dateFormat;
            $('#startDate').text($.datepicker.formatDate( dateFormat, startDate, inst.settings ));
            $('#endDate').text($.datepicker.formatDate( dateFormat, endDate, inst.settings ));
            selectCurrentWeek();
        },
        beforeShowDay: function(date) {
            var cssClass = '';
            if(date >= startDate && date <= endDate)
                cssClass = 'ui-datepicker-current-day';
            return [true, cssClass];
        },
        onChangeMonthYear: function(year, month, inst) {
            selectCurrentWeek();
        },
        onSelect : function(){
        $('#weekDate').submit();   
    }
    });
    $('.week-picker .ui-datepicker-calendar tr').live('mousemove', function() { $(this).find('td a').addClass('ui-state-hover'); });
    $('.week-picker .ui-datepicker-calendar tr').live('mouseleave', function() { $(this).find('td a').removeClass('ui-state-hover'); });
});

然后我有一个名为"weekDate"的HTML表单，用于在用户选择日期时触发onSelect Datepicker函数时捕获startDate和endDate值:

<form id="weekDate" name="weekDate" action="~" method="post"> 
    <input type="hidden" id="startDate" name="startDate" class="week-picker" />
    <input type="hidden" id="endDate" name="endDate" class="week-picker" />
</form>

然后我有一个PHP页面希望捕捉#startDate和#endDate作为POST变量的值:

$UpWeekStart = $_POST['startDate'];
$UpWeekEnd = $_POST['endDate'];

我的问题:当我尝试回显$UpWeekStart和$UpWeekEnd时，输出为空白。请帮助。