js日期格式化函数&&日期加减

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Date.prototype.format = function (fmt) {

    var year = this.getFullYear();

    var month = this.getMonth() + 1;

    var date = this.getDate();

 

    fmt = fmt.replace("yyyy", year);

    fmt = fmt.replace("yy", year % 100);

    fmt = fmt.replace("MM", fix(month));

    fmt = fmt.replace("dd", fix(this.getDate()));

    fmt = fmt.replace("HH", fix(this.getHours()));

    fmt = fmt.replace("mm", fix(this.getMinutes()));

    fmt = fmt.replace("ss", fix(this.getSeconds()));

    return fmt;

    function fix(n) {

        return n < 10 ? "0" + n : n;

    }

}

 使用：
var date1 = new Date(selectedDate);
var newDate = new Date(date1.getTime() + 24 * 60 * 60 * 1000); //加一天
var newDateStr = newDate.format("yyyy-MM-dd");
$("#txtDay2").val(newDateStr);