【关于时间戳】

原文：https://zhuanlan.zhihu.com/p/450208567

1.获取时间戳

javascript 复制代码

第一种
var timestamp = Date.parse(new Date());
输出：1640569738000
第二种
var timestamp=new Date().getTime()；
输出：1640569787716
第三种
var timestamp=new Date().getTime()；(和二重复了)
var timestamp = (new Date()).valueOf() 
输出：1640569936666</code>

第一种：获取的时间戳是把毫秒改成000显示，因为这种方式只精确到秒

第二种和第三种是获取了当前毫秒的时间戳。

2.获取时间

javascript 复制代码

var myDate = new Date();
myDate.getYear();  //获取当前年份(2位)
myDate.getFullYear(); //获取完整的年份(4位,1970-????)
myDate.getMonth();  //获取当前月份(0-11,0代表1月)
myDate.getDate();  //获取当前日(1-31)
myDate.getDay();   //获取当前星期X(0-6,0代表星期天)
myDate.getTime();  //获取当前时间(从1970.1.1开始的毫秒数)
myDate.getHours();  //获取当前小时数(0-23)
myDate.getMinutes();  //获取当前分钟数(0-59)
myDate.getSeconds();  //获取当前秒数(0-59)
myDate.getMilliseconds(); //获取当前毫秒数(0-999)
myDate.toLocaleDateString();  //获取当前日期
var mytime=myDate.toLocaleTimeString();  //获取当前时间
myDate.toLocaleString( );  //获取日期与时间


// 获取当前时间戳(以s为单位)
var timestamp = Date.parse(new Date());
timestamp = timestamp / 1000;
//当前时间戳为：1403149534
console.log("当前时间戳为：" + timestamp);
 
// 获取某个时间格式的时间戳
var stringTime = "2014-07-10 10:21:12";
var timestamp2 = Date.parse(new Date(stringTime));
timestamp2 = timestamp2 / 1000;
//2014-07-10 10:21:12的时间戳为：1404958872 
console.log(stringTime + "的时间戳为：" + timestamp2);
 
// 将当前时间换成时间格式字符串
var timestamp3 = 1403058804;
var newDate = new Date();
newDate.setTime(timestamp3 * 1000);
// Wed Jun 18 2014 
console.log(newDate.toDateString());
// Wed, 18 Jun 2014 02:33:24 GMT 
console.log(newDate.toGMTString());
// 2014-06-18T02:33:24.000Z
console.log(newDate.toISOString());
// 2014-06-18T02:33:24.000Z 
console.log(newDate.toJSON());
// 2014年6月18日 
console.log(newDate.toLocaleDateString());
// 2014年6月18日 上午10:33:24 
console.log(newDate.toLocaleString());
// 上午10:33:24 
console.log(newDate.toLocaleTimeString());
// Wed Jun 18 2014 10:33:24 GMT+0800 (中国标准时间)
console.log(newDate.toString());
// 10:33:24 GMT+0800 (中国标准时间) 
console.log(newDate.toTimeString());
// Wed, 18 Jun 2014 02:33:24 GMT
console.log(newDate.toUTCString());

3.时间戳转化为YYYY-MM-DD hh:mm:ss

javascript 复制代码

function timestampToTime(timestamp) {
        var date = new Date(timestamp * 1000);//时间戳为10位需*1000，时间戳为13位的话不需乘1000
        var Y = date.getFullYear() + '-';
        var M = (date.getMonth()+1 < 10 ? '0'+(date.getMonth()+1):date.getMonth()+1) + '-';
        var D = (date.getDate()< 10 ? '0'+date.getDate():date.getDate())+ ' ';
        var h = (date.getHours() < 10 ? '0'+date.getHours():date.getHours())+ ':';
        var m = (date.getMinutes() < 10 ? '0'+date.getMinutes():date.getMinutes()) + ':';
        var s = date.getSeconds() < 10 ? '0'+date.getSeconds():date.getSeconds();
        return Y+M+D+h+m+s;
    }
 timestampToTime(1403058804);
 console.log(timestampToTime(1403058804));//2020-06-18 10:33:24

4.封装的时间格式器

javascript 复制代码

/** 
 * 时间戳格式化函数 
 * @param {string} format 格式 
 * @param {int} timestamp 要格式化的时间 默认为当前时间 
 * @return {string}   格式化的时间字符串 
 */
function date(format, timestamp){ 
 var a, jsdate=((timestamp) ? new Date(timestamp*1000) : new Date()); 
 var pad = function(n, c){ 
  if((n = n + "").length < c){ 
   return new Array(++c - n.length).join("0") + n; 
  } else { 
   return n; 
  } 
 }; 
 var txt_weekdays = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"]; 
 var txt_ordin = {1:"st", 2:"nd", 3:"rd", 21:"st", 22:"nd", 23:"rd", 31:"st"}; 
 var txt_months = ["", "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]; 
 var f = { 
  // Day 
  d: function(){return pad(f.j(), 2)}, 
  D: function(){return f.l().substr(0,3)}, 
  j: function(){return jsdate.getDate()}, 
  l: function(){return txt_weekdays[f.w()]}, 
  N: function(){return f.w() + 1}, 
  S: function(){return txt_ordin[f.j()] ? txt_ordin[f.j()] : 'th'}, 
  w: function(){return jsdate.getDay()}, 
  z: function(){return (jsdate - new Date(jsdate.getFullYear() + "/1/1")) / 864e5 >> 0}, 
// Week
W: function(){
var a = f.z(), b = 364 + f.L() - a;
var nd2, nd = (new Date(jsdate.getFullYear() + "/1/1").getDay() || 7) - 1;
if(b <= 2 && ((jsdate.getDay() || 7) - 1) <= 2 - b){
return 1;
} else{
if(a <= 2 && nd >= 4 && a >= (6 - nd)){
nd2 = new Date(jsdate.getFullYear() - 1 + "/12/31");
return date("W", Math.round(nd2.getTime()/1000));
} else{
return (1 + (nd <= 3 ? ((a + nd) / 7) : (a - (7 - nd)) / 7) >> 0);
}
}
},

// Month
F: function(){return txt_months[f.n()]},
m: function(){return pad(f.n(), 2)},
M: function(){return f.F().substr(0,3)},
n: function(){return jsdate.getMonth() + 1},
t: function(){
var n;
if( (n = jsdate.getMonth() + 1) == 2 ){
return 28 + f.L();
} else{
if( n & 1 && n < 8 || !(n & 1) && n > 7 ){
return 31;
} else{
return 30;
}
}
},

// Year
L: function(){var y = f.Y();return (!(y & 3) && (y % 1e2 || !(y % 4e2))) ? 1 : 0},
//o not supported yet
Y: function(){return jsdate.getFullYear()},
y: function(){return (jsdate.getFullYear() + "").slice(2)},

// Time
a: function(){return jsdate.getHours() > 11 ? "pm" : "am"},
A: function(){return f.a().toUpperCase()},
B: function(){
// peter paul koch:
var off = (jsdate.getTimezoneOffset() + 60)60;
var theSeconds = (jsdate.getHours() 3600) + (jsdate.getMinutes() 60) + jsdate.getSeconds() + off;
var beat = Math.floor(theSeconds/86.4);
if (beat > 1000) beat -= 1000;
if (beat < 0) beat += 1000;
if ((String(beat)).length 1) beat = "00"+beat;
if ((String(beat)).length 2) beat = "0"+beat;
return beat;
},
g: function(){return jsdate.getHours() % 12 || 12},
G: function(){return jsdate.getHours()},
h: function(){return pad(f.g(), 2)},
H: function(){return pad(jsdate.getHours(), 2)},
i: function(){return pad(jsdate.getMinutes(), 2)},
s: function(){return pad(jsdate.getSeconds(), 2)},
//u not supported yet

// Timezone
//e not supported yet
//I not supported yet
O: function(){
var t = pad(Math.abs(jsdate.getTimezoneOffset()/60100), 4);
if (jsdate.getTimezoneOffset() > 0) t = "-" + t; else t = "+" + t;
return t;
},
P: function(){var O = f.O();return (O.substr(0, 3) + ":" + O.substr(3, 2))},
//T not supported yet
//Z not supported yet

// Full Date/Time
c: function(){return f.Y() + "-" + f.m() + "-" + f.d() + "T" + f.h() + ":" + f.i() + ":" + f.s() + f.P()},
//r not supported yet
U: function(){return Math.round(jsdate.getTime()/1000)}
};

return format.replace(/[]?([a-zA-Z])/g, function(t, s){
if( t!=s ){
// escaped
ret = s;
} else if( f[s] ){
// a date function exists
ret = fs;
} else{
// nothing special
ret = s;
}
return ret;
});
}