JavaScript代码中常用的时间对象

创建时间对象

1. var currentDate = new Date();
   
2. var specificDate = new Date(2024, 4, 28, 8, 50, 0, 0);

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获取年份

1. var currentDate = new Date();
   
2. var year = currentDate.getFullYear();
   
3. console.log(year);

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获取月份

1. var currentDate = new Date();
   
2. var month = currentDate.getMonth() + 1;
   
3. console.log(month);

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获取日期

1. var currentDate = new Date();
   
2. var date = currentDate.getDate();
   
3. console.log(date);

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获取星期

1. var currentDate = new Date();
   
2. var dayOfWeek = currentDate.getDay();
   
3. var daysOfWeek = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'];
   
4. var dayName = daysOfWeek[dayOfWeek];
   
5. console.log(dayName);

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获取小时

1. var currentDate = new Date();
   
2. var hours = currentDate.getHours();
   
3. console.log(hours);

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获取秒数

1. var currentDate = new Date();
   
2. var seconds = currentDate.getSeconds();
   
3. console.log(seconds);

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获取当前时间戳

1. var currentDate = new Date();
   
2. var timestamp = currentDate.getTime();
   
3. console.log(timestamp);

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转换当前时间戳

1. var currentDate = new Date();
   
2. var timestamp = currentDate.getTime();
   
3. console.log(timestamp);

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指定日期转时间戳

1. var specifiedDate = new Date(2024, 4, 28);
   
2. var timestamp = specifiedDate.getTime();
   
3. console.log(timestamp);

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时间戳转日期

1. var timestamp = 1622195912345;
   
2. var date = new Date();
   
3. date.setTime(timestamp);
   
4. var year = date.getFullYear();
   
5. var month = date.getMonth() + 1;
   
6. var day = date.getDate();
   
7. console.log(year + '-' + month + '-' + day);

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计算两个世界的间隔

1. var startDate = new Date('2024-05-01');
   
2. var endDate = new Date('2024-05-10');
   
3. var startTimestamp = startDate.getTime();
   
4. var endTimestamp = endDate.getTime();
   
5. var millisecondsPerDay = 24 * 60 * 60 * 1000;
   
6. var daysInterval = Math.round((endTimestamp - startTimestamp) / millisecondsPerDay);
   
7. console.log(daysInterval);

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判断时间是否正确

1. function isValidDate(dateString) {
   
2.     var regex = /^\d{4}-\d{2}-\d{2}$/;
   
3.     if (!regex.test(dateString)) {
   
4.         return false;
   
5.     }
   
6.     var date = new Date(dateString);
   
7.     var year = date.getFullYear();
   
8.     var month = date.getMonth() + 1;
   
9.     var day = date.getDate();
   
10.     if (month < 1 || month > 12) {
    
11.         return false;
    
12.     }
    
13.     var daysInMonth = new Date(year, month, 0).getDate();
    
14.     if (day < 1 || day > daysInMonth) {
    
15.         return false;
    
16.     }
    
17.     return true;
    
18. }
    
19. var dateString = '2024-02-30';
    
20. console.log(isValidDate(dateString));

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确定日期再哪一年的第几天

1. function dayOfYear(dateString) {
   
2.     var date = new Date(dateString);
   
3.     var startOfYear = new Date(date.getFullYear(), 0, 0);
   
4.     var diff = date - startOfYear;
   
5.     var oneDay = 1000 * 60 * 60 * 24;
   
6.     var day = Math.floor(diff / oneDay);
   
7.     return day;
   
8. }
   
9. // 示例用法
   
10. var dateString = '2024-05-28';
    
11. var day = dayOfYear(dateString);
    
12. console.log(day);

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格式化时间

1. function formatTime(date) {
   
2.     var hours = date.getHours().toString().padStart(2, '0');
   
3.     var minutes = date.getMinutes().toString().padStart(2, '0');
   
4.     var seconds = date.getSeconds().toString().padStart(2, '0');
   
5.     return hours + ':' + minutes + ':' + seconds;
   
6. }
   
7. var now = new Date();
   
8. var formattedTime = formatTime(now);
   
9. console.log(formattedTime);

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