JavaScript 计算时间差并格式化输出

工具方法代码如下：

/**
     * 获取时间差
     * @param timeStart
     * @param timeEnd
     */
    function getCostTimeString(timeStart, timeEnd,level) {
   
        var timeCost = timeEnd.getTime() - timeStart.getTime(); //时间差的毫秒数
        var days = Math.floor(timeCost / (24 * 3600 * 1000)); // 计算出相差天数
        //计算出小时数
        var leave1 = timeCost % (24 * 3600 * 1000); //计算天数后剩余的毫秒数
        var hours = Math.floor(leave1 / (3600 * 1000));
        //计算出相差分钟数
        var leave2 = leave1 % (3600 * 1000); //计算小时数后剩余的毫秒数
        var minutes = Math.floor(leave2 / (60 * 1000));
        //计算出相差秒数
        var leave3 = leave2 % (60 * 1000); //计算分钟数后剩余的毫秒数
        var seconds = Math.round(leave3 / 1000);
        if (level === 1) {
   
            return seconds + "秒";
        }
        if (level === 2) {
   
            return minutes + "分钟" + seconds + "秒";
        }
        if (level === 3) {
   
            return hours+"小时"+minutes + "分钟" + seconds + "秒";
        }
        if (level === 4) {
   
            return days + "天" + hours + "小时" + minutes + "分钟" + seconds + "秒";
        }
        return minutes + "分钟" + seconds + "秒";
    }