js获取昨天日期

刚刚js做项目,遇到需要获取昨天日期的问题,网上找了下答案,感觉网上的答案都不太严谨,自己写了个,凑合能用吧,忘大神们抛砖指教.

<script type="text/javascript" language="javascript">
    function getYestoday(date){
        var arrMonth = new Array([0], [31], [28], [31], [30], [31], [30], [31], [31], [30], [31], [30], [31]);//初始化月份(第一个0,占位作用,让下标和月份对应)
        var strYear = date.getFullYear();//获取年份
        var strDay = date.getDate();//获取日期
        var strMonth = date.getMonth() + 1;//获取月份
        ///判断是否是闰年
        if (strYear % 4 == 0 && strYear % 100 != 0) {
            arrMonth[2] = 29;
        }
        ///判断日期是否是第一天
        if (strDay - 1 == 0) {
            ///判断月份是否是一月
            if (strMonth - 1 == 0) {
                strYear -= 1;
                strMonth = 12;
            } else {
                strMonth -= 1;
            }
            strDay = arrMonth[strMonth];
        } else {
            strDay -= 1;
        }
        ///月份小于10,前面加0
        if (strMonth < 10) {
            strMonth = "0" + strMonth;
        }
        ///日期小于10,前面加0
        if (strDay < 10) {
            strDay = "0" + strDay;
        }
        return strYear + "-" + strMonth + "-" + strDay;
    }
    alert(getYestoday(new Date("2012-1-1")));//测试日期
</script>