Time object
Acquisition of time
// 1. Get the current time object
var date = new Date(a);// The current time object, note: this time is your computer time, usually used from the server time
console.log(date);
// 2. The time of the object can be set
2.1 Setting the time Mode 1:
// The parameters are year month (note: 0-11 months) day minutes and seconds
var date = new Date("2020"."Seven"."3");// Note that the "7" here stands for August
console.log(date);//Mon Aug 03 2020 00:00:00 GMT+0800
//2.2 Setting the time Mode 2: The month is From January to December
// The year can be - /.
var date = new Date("The 2020-8-5 14:20:14");// Note that 8-5 represents August 5
console.log(date);//Wed Aug 05 2020 14:20:14 GMT+0800
Copy the codeOperation of time
var nowDate = new Date(a);console.log(nowDate);// Get the current time
// 1. Get year getFullYear; Note: parentheses are required
var year = nowDate.getFullYear();
console.log(year);
// 2. Get month; Note in particular that the month from 0 to 11 is also indexed
var month = nowDate.getMonth();
console.log(month+1); // The month must be incremented by 1
// 3. Get day getDate
var day = nowDate.getDate();
console.log(day);
// 4. Get week getDay
var day = nowDate.getDay(); // Especially to be distinguished from fetching days; Sunday is the implementation of 0, the rest normal 1-6;
console.log(day);
// 5. Access time: 24 hours
var hour = nowDate.getHours();
console.log(hour);
// 6.
var minute = nowDate.getMinutes();
console.log(minute);
// 7. Get seconds
var second = nowDate.getSeconds();
console.log(second); Summary: When getting the month, pay special attention to the month0-11Also index, execution is required to add1; Notice the difference between day and day.Copy the codeWrite a clock JS
1. Obtain the current hour, minute, and second;
2. Minute = second to component + current minute;
3. Hour: the time when minutes turn into hours + the current hour;
// This version of the page will be refreshed from 0 to 1 second before the current rotation, user experience is not very good
setInterval(function(){
var date = new Date(a);// The current time is the computer time
var msecond = date.getMilliseconds(); // Get the number of milliseconds
var second = date.getSeconds()+msecond/1000; // Get the current second
var minute = date.getMinutes() + second / 60; // Get the time of current minute + current second
var hour = date.getHours() + minute / 60; // Get the hours of the current hour + the current minute and second;
// var myhour = date.getHours()>12?date.getHours()-12:date.getHours();
/ / calculate Angle
var dsecond = second / 60 * 360+msecond/1000;; // The Angle of the second
var dminute = minute / 60 * 360; // Divide the Angle occupied
var dhour = hour / 12 * 360;
hourEle.style.transform = "rotate(" + dhour + "deg)";
minuteEle.style.transform = "rotate(" + dminute + "deg)";
secondEle.style.transform = "rotate(" + dsecond + "deg)";
},1000)
Copy the code// Slightly optimize the version
var run = function () {
var date=new Date(a);// Get the current time;
var msecond = date.getMilliseconds(); // Get the number of milliseconds
var second = date.getSeconds()+msecond/1000; // Get the current second
var minute = date.getMinutes() + second / 60; // Get the time of current minute + current second
var hour = date.getHours() + minute / 60;// Get the hours of the current hour + the current minute and second;
// Calculate the Angle
var dsecond = second / 60 * 360; // The Angle of the second
var dminute = minute / 60 * 360; // Divide the Angle occupied
var dhour = hour / 12 * 360;
// The first is the id name
hourEle.style.transform = "rotate(" + dhour + "deg)";
minuteEle.style.transform = "rotate(" + dminute + "deg)";
secondEle.style.transform = "rotate(" + dsecond + "deg)";
}
run(); // The browser executes it once it enters
setInterval(run,1000);// The interval will be executed after 1 second
Copy the code2. Timestamp
Time stamp: the number of milliseconds in a time from Greenwich Mean Time (00:00.00, January 1, 1970);
How to get a timestamp: time object.getTime ();
var date = new Date(a);var time = date.getTime();
console.log(time); // The current timestamp is the number of milliseconds from Greenwich Mean Time.
Copy the codeThe use of time stamps: can do the actual difference between 2 times; Or countdown, seconds kill.
Note: timestamps in JS are milliseconds, and in many background timestamps are seconds.
Do a countdown
Generally, the time is obtained from the server
function fn(){
var mdate=new Date("The 2021-8-29 08:36:25")
var nowdate=new Date(a);var mtimeStamp=mdate.getTime();
var nowtimeStamp=nowdate.getTime();
var time=(mtimeStamp-nowtimeStamp)/1000;// The time difference between the two
}
function run() {
// 1.
var mdate = new Date("The 2021-09-01 09:00:00"); // Monday at 9 a.m
// console.log(mdate);
// 2. The current time object
var nowDate = new Date(a);// The current time object
// 3. Obtain the timestamp of the object and calculate the time difference between the two
var mtimeStamp = mdate.getTime(); // Time stamp for class on Monday;
var nowTimeStamp = nowDate.getTime(); // The timestamp of the current time;
// The time difference from Monday
var time = parseInt((mtimeStamp - nowTimeStamp) / 1000);// The timestamp calculates milliseconds, we need to convert to seconds, then do the following day/hour/minute/second conversion.
// console.log(time);
// Count the days
var day = parseInt(time / 3600 / 24);
// console.log(day);
// Count the hours
var hour = parseInt(time / 3600) % 24
// console.log(hour);
// Count the minutes
var minute = parseInt(time / 60) % 60;
// console.log(minute)
/ / calculate the seconds
var second = parseInt(time % 60);
// console.log(second);
// document.write(" + day + day + hour + hour + minute + second + second "); // Write once every second
// Replace the HTML code
document.body.innerHTML = "There's still time for class on Monday." + day + "Day" + hour + "Hour" + minute + "Minutes" + second + "Seconds";
}
setInterval(run, 1000);// The interval is executed every 1 second
Copy the codeSummary idea: obtain the corresponding time stamps for the two countdown times, then calculate the time difference between the two times (), and finally convert the time difference into the corresponding day/hour/minute/second.