js怎么计算天数

function calculateDaysBetweenDates(date1, date2) {
    // 获取两个日期的毫秒数
    const timeDifference = date2.getTime() - date1.getTime();
    
    // 将毫秒数转换为天数
    const daysDifference = Math.floor(timeDifference / (1000 * 60 * 60 * 24));
    
    return daysDifference;
}

// 示例使用
const startDate = new Date('2023-10-01');
const endDate = new Date('2023-10-10');
const days = calculateDaysBetweenDates(startDate, endDate);
console.log(`天数差: ${days}`); // 输出: 天数差: 9

function calculateDaysFromToday(targetDate) {
    const today = new Date();
    const timeDifference = targetDate.getTime() - today.getTime();
    const daysDifference = Math.floor(timeDifference / (1000 * 60 * 60 * 24));
    return daysDifference;
}

// 示例使用
const targetDate = new Date('2023-12-25');
const daysFromToday = calculateDaysFromToday(targetDate);
console.log(`距离目标日期还有 ${daysFromToday} 天`);