Jquery日期选择器以一些日期以粗体格式

var events = {};
events[new Date('02/14/2011')] = new Event('Valentines Day','mybold');
events[new Date('02/18/2011')] = new Event('Payday','mybold');
    $('#calender').datepicker({
        changeMonth : true,changeYear : true,beforeShowDay : function(datE) {
            var event = events[date];
            if (event) {
                return [ true,'mybold',event.text ];
            } else {
                return [ true,'','' ];
            }
        }
    });
.
.
.
.
<style>
.mybold>a {
    font-weight:bold;
    BACkground-color: yellow !important; 
    BACkground-image: none !important;
}
</style>

它将背景颜色显示为黄色但未以粗体显示文本？
谢谢