JavaScript Object Programming-3rd Chapter

Directory

• Date Object
• Math Object
• Array Object
• String Object
• Regular Expression Object

What is an object

Objects have properties and methods, properties of various data types, and methods to manipulate the data in a property.

Object of JavaScript

• Built-in objects
  Date, Array, String, Math, number, and so on
• Browser Object
  Window, Frame, Navigator, History, location, screen, document, etc.
• Custom Objects

Date Object

1. var Date object = new Date ()
2. var Date object = new Date (number of milliseconds)
3. var Date object = new Date (string)
4. var Date object = new Date (year, month, day, etc. parameters)

var  mydate=new Date(5000);var mydate=new Date( );document.write(mydate);

Time: UTC Global Standard Time, also known as Greenwich Mean Time, utc+800 refers to 8 hours earlier than Greenwich Standard Time, also Beijing time.

Method of the Date object

Parameters for the Date object method

• months:0 to 11
• Date:1 to 31
• Day:0 to 6
• hours:0 to 23
• Seconds and minutes:0 to 59

To method:

• toLocaleString
• toGMTString

var now= new Date( ) ;//获得当前日期和时间var hour = now.getHours() ;//获得小时，即当前是几点setTimeout( )方法每隔1秒调用显示时间

Math Object

The Math object, which is more complex than the inherited mathematical operations.

Common Properties and methods

PIabs(x)绝对值sin (x) 正弦random()随机数round(x)四舍五入sqrt(x)平方根

Array

var myarray= new Array ()
var myarray= []

Properties and Methods

lengthjoin()将数组中所有元素转化为字符串reverse()将数组中元素完全颠倒sort()排列数组

Traversal of an array

for (var i=0;i<MyArray.length;i++){ document.write(MyArray[i]);}for (var i in MyArray){ document.write(MyArray[i]);}

String Object

var str = new String (“这是字符串")

Common properties and methods for String objects

lengthsplit(  )indexOf(“子字符串”，起始位置 ) lastIndexOf (“子字符串”，起始位置 ) charAt( index )

Regular expressions

Regular expressions are strings, divided into simple patterns and complex patterns.

var reg=/china/;var reg=/^\w+$/;

/[a-z0-9.] /can match any one character in A-Z, 0-9, and.

Regular expression symbols

\s 任何空白字符\d 匹配一个数字字符，等价于[0-9]\w 匹配一个数字、下划线或字母字符，等价于[A-Za-z0-9_]\W 任何非单字字符，等价于[^a-zA-z0-9_]

Conclusion

JavaScript Object Programming-3rd Chapter