JavaScript Date (date) related knowledge and usage

JavaScript Date (date) is widely used in web pages. This article explains it in detail.

Creation Date

Date object is used to handle date and time.

Date objects can be defined through the new keyword. The following code defines a Date object named myDate:

There are four ways to initialize the date:

new Date() // 当前日期和时间
new Date(milliseconds) //返回从 1970 年 1 月 1 日至今的毫秒数
new Date(dateString)
new Date(year, month, day, hours, minutes, seconds, milliseconds)

Most of the above parameters are optional. If not specified, the default The parameter is 0.

Some examples of instantiating a date:

var today = new Date()
var d1 = new Date("October 13, 1975 11:13:00")
var d2 = new Date(79,5,24)
var d3 = new Date(79,5,24,11,33,0)

Set Date

We can easily operate on dates by using methods on date objects.

In the following example, we set a specific date (January 14, 2010) for the date object:

var myDate=new Date();
myDate.setFullYear(2010,0,14);

In the following example, we set the date object to Date 5 days later:

var myDate=new Date();
myDate.setDate(myDate.getDate()+5);

Note: If adding days would change the month or year, the date object will automatically complete this conversion.

Comparison of two dates

Date objects can also be used to compare two dates.

The following code compares the current date with January 14, 2100:

var x=new Date();
x.setFullYear(2100,0,14);
var today = new Date();if (x>today){    
alert("今天是2100年1月14日之前");}
else{   
 alert("今天是2100年1月14日之后");
 }

This article introduces in detail the specific usage of Date in js and related precautions, more For relevant knowledge, please pay attention to the php Chinese website.

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