版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/benben_2015/article/details/88824364
JavaScript获取时间戳的三个方法：
- Date.parse(new Date())
获取13位时间戳，例如1553581293000， - (new Date()).valueOf()
获取13位时间戳，精确到毫秒，例如：1553581461549 - new Date().getTime()。
获取13位时间戳，精确到毫秒，例如：1553581482325
示例
以上面第一种方法为例
<!DOCTYPE html>
<html>
<body>
<p id="demo">timestamp</p>
<button type="button" onclick="myFunction()">点击这里，显示时间戳</button>
<script>
function myFunction() {
document.getElementById("demo").innerHTML = Date.parse(new Date());
}
</script>
</body>
</html>
上述页面中的脚本执行后，会返回13位数字，如：1553581461549。parse方法会解析包含日期的字符串，并返回该日期与1970年1月1日午夜之间的毫秒数（UTC时间）。而上面parse解析的字符串是通过new Date()方法来获取到的，从下面的内容来看，new Date()获取的是一个当前主机的本地时间。
/** Enables basic storage and retrieval of dates and times. */
interface Date {
/** Returns a string representation of a date. The format of the string depends on the locale. */
toString(): string;
/** Returns a date as a string value. */
toDateString(): string;
/** Returns a time as a string value. */
toTimeString(): string;
/** Returns a value as a string value appropriate to the host environment's current locale. */
toLocaleString(): string;
/** Returns a date as a string value appropriate to the host environment's current locale. */
toLocaleDateString(): string;
/** Returns a time as a string value appropriate to the host environment's current locale. */
toLocaleTimeString(): string;
/** Returns the stored time value in milliseconds since midnight, January 1, 1970 UTC. */
valueOf(): number;
/** Gets the time value in milliseconds. */
getTime(): number;
/** Gets the year, using local time. */
getFullYear(): number;
/** Gets the year using Universal Coordinated Time (UTC). */
getUTCFullYear(): number;
/** Gets the month, using local time. */
getMonth(): number;
/** Gets the month of a Date object using Universal Coordinated Time (UTC). */
getUTCMonth(): number;
/** Gets the day-of-the-month, using local time. */
getDate(): number;
/** Gets the day-of-the-month, using Universal Coordinated Time (UTC). */
getUTCDate(): number;
/** Gets the day of the week, using local time. */
getDay(): number;
/** Gets the day of the week using Universal Coordinated Time (UTC). */
getUTCDay(): number;
/** Gets the hours in a date, using local time. */
getHours(): number;
/** Gets the hours value in a Date object using Universal Coordinated Time (UTC). */
getUTCHours(): number;
/** Gets the minutes of a Date object, using local time. */
getMinutes(): number;
/** Gets the minutes of a Date object using Universal Coordinated Time (UTC). */
getUTCMinutes(): number;
/** Gets the seconds of a Date object, using local time. */
getSeconds(): number;
/** Gets the seconds of a Date object using Universal Coordinated Time (UTC). */
getUTCSeconds(): number;
/** Gets the milliseconds of a Date, using local time. */
getMilliseconds(): number;
/** Gets the milliseconds of a Date object using Universal Coordinated Time (UTC). */
getUTCMilliseconds(): number;
/** Gets the difference in minutes between the time on the local computer and Universal Coordinated Time (UTC). */
getTimezoneOffset(): number;
/**
* Sets the date and time value in the Date object.
* @param time A numeric value representing the number of elapsed milliseconds since midnight, January 1, 1970 GMT.
*/
setTime(time: number): number;
/**
* Sets the milliseconds value in the Date object using local time.
* @param ms A numeric value equal to the millisecond value.
*/
setMilliseconds(ms: number): number;
/**
* Sets the milliseconds value in the Date object using Universal Coordinated Time (UTC).
* @param ms A numeric value equal to the millisecond value.
*/
setUTCMilliseconds(ms: number): number;
/**
* Sets the seconds value in the Date object using local time.
* @param sec A numeric value equal to the seconds value.
* @param ms A numeric value equal to the milliseconds value.
*/
setSeconds(sec: number, ms?: number): number;
/**
* Sets the seconds value in the Date object using Universal Coordinated Time (UTC).
* @param sec A numeric value equal to the seconds value.
* @param ms A numeric value equal to the milliseconds value.
*/
setUTCSeconds(sec: number, ms?: number): number;
/**
* Sets the minutes value in the Date object using local time.
* @param min A numeric value equal to the minutes value.
* @param sec A numeric value equal to the seconds value.
* @param ms A numeric value equal to the milliseconds value.
*/
setMinutes(min: number, sec?: number, ms?: number): number;
/**
* Sets the minutes value in the Date object using Universal Coordinated Time (UTC).
* @param min A numeric value equal to the minutes value.
* @param sec A numeric value equal to the seconds value.
* @param ms A numeric value equal to the milliseconds value.
*/
setUTCMinutes(min: number, sec?: number, ms?: number): number;
/**
* Sets the hour value in the Date object using local time.
* @param hours A numeric value equal to the hours value.
* @param min A numeric value equal to the minutes value.
* @param sec A numeric value equal to the seconds value.
* @param ms A numeric value equal to the milliseconds value.
*/
setHours(hours: number, min?: number, sec?: number, ms?: number): number;
/**
* Sets the hours value in the Date object using Universal Coordinated Time (UTC).
* @param hours A numeric value equal to the hours value.
* @param min A numeric value equal to the minutes value.
* @param sec A numeric value equal to the seconds value.
* @param ms A numeric value equal to the milliseconds value.
*/
setUTCHours(hours: number, min?: number, sec?: number, ms?: number): number;
/**
* Sets the numeric day-of-the-month value of the Date object using local time.
* @param date A numeric value equal to the day of the month.
*/
setDate(date: number): number;
/**
* Sets the numeric day of the month in the Date object using Universal Coordinated Time (UTC).
* @param date A numeric value equal to the day of the month.
*/
setUTCDate(date: number): number;
/**
* Sets the month value in the Date object using local time.
* @param month A numeric value equal to the month. The value for January is 0, and other month values follow consecutively.
* @param date A numeric value representing the day of the month. If this value is not supplied, the value from a call to the getDate method is used.
*/
setMonth(month: number, date?: number): number;
/**
* Sets the month value in the Date object using Universal Coordinated Time (UTC).
* @param month A numeric value equal to the month. The value for January is 0, and other month values follow consecutively.
* @param date A numeric value representing the day of the month. If it is not supplied, the value from a call to the getUTCDate method is used.
*/
setUTCMonth(month: number, date?: number): number;
/**
* Sets the year of the Date object using local time.
* @param year A numeric value for the year.
* @param month A zero-based numeric value for the month (0 for January, 11 for December). Must be specified if numDate is specified.
* @param date A numeric value equal for the day of the month.
*/
setFullYear(year: number, month?: number, date?: number): number;
/**
* Sets the year value in the Date object using Universal Coordinated Time (UTC).
* @param year A numeric value equal to the year.
* @param month A numeric value equal to the month. The value for January is 0, and other month values follow consecutively. Must be supplied if numDate is supplied.
* @param date A numeric value equal to the day of the month.
*/
setUTCFullYear(year: number, month?: number, date?: number): number;
/** Returns a date converted to a string using Universal Coordinated Time (UTC). */
toUTCString(): string;
/** Returns a date as a string value in ISO format. */
toISOString(): string;
/** Used by the JSON.stringify method to enable the transformation of an object's data for JavaScript Object Notation (JSON) serialization. */
toJSON(key?: any): string;
}
interface DateConstructor {
new(): Date;
new(value: number | string): Date;
new(year: number, month: number, date?: number, hours?: number, minutes?: number, seconds?: number, ms?: number): Date;
(): string;
readonly prototype: Date;
/**
* Parses a string containing a date, and returns the number of milliseconds between that date and midnight, January 1, 1970.
* @param s A date string
*/
parse(s: string): number;
/**
* Returns the number of milliseconds between midnight, January 1, 1970 Universal Coordinated Time (UTC) (or GMT) and the specified date.
* @param year The full year designation is required for cross-century date accuracy. If year is between 0 and 99 is used, then year is assumed to be 1900 + year.
* @param month The month as an number between 0 and 11 (January to December).
* @param date The date as an number between 1 and 31.
* @param hours Must be supplied if minutes is supplied. An number from 0 to 23 (midnight to 11pm) that specifies the hour.
* @param minutes Must be supplied if seconds is supplied. An number from 0 to 59 that specifies the minutes.
* @param seconds Must be supplied if milliseconds is supplied. An number from 0 to 59 that specifies the seconds.
* @param ms An number from 0 to 999 that specifies the milliseconds.
*/
UTC(year: number, month: number, date?: number, hours?: number, minutes?: number, seconds?: number, ms?: number): number;
now(): number;
}
问题来了，一般服务器的时间是固定的，但是客户端且分布世界各地，客户端系统设置的时间也不一定按标准时区分布。因此就会造成通过JavaScript得到的时间戳不准确。