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Brief introduction:

Description: JS provides three special reference types: Boolean, number, String, when assigned to a variable as a primitive type object, the background creates an object of the corresponding base wrapper type, enabling you to invoke some methods to manipulate these types of data

Literal create var content = ' I love you! ' var subcontent = content.substring (2) Console.log (subcontent)//new string Create var content = new String (' I love you! ') var subcontent = content.substring (2) console.log (subcontent)

Note: You can see from the above that both the wrapper object created by the default literal or the reference type object created by new are properties and methods, but it is important to note that the wrapper object created by the literal cannot add properties and methods, only the reference type object created by new supports adding properties and methods.

Boolean type:

Description: The Boolean type does not have a specific property or method

Number type:

Description: The number type has some static properties (directly from the property called by number, ignoring the new operator) and methods

Static properties
Max_value	Represents the maximum number
Min_value	Represents the minimum value
NaN	Non-numeric
Negative_infinity	Negative infinity, overflow returns this value
Positive_infinity	Infinity, Overflow returns this value
Prototype	Prototypes. For adding new properties and methods
Object methods
ToString ()	Converts a value to a string, and can be converted into a binary
toLocaleString ()	Converts to a string based on a local number format, separated by a three-bit separated comma
ToFixed ()	Preserves a number by specifying the number of digits after the decimal point and converting it to a string, expressed as a normal floating point

String type:

Object Properties
Length	Returns the character length of a string
Constructor	Returns the function that creates a String object
Prototype	Extending a string definition by adding properties and methods
Static methods
fromCharCode (ASCII)	static method, output ASCII code corresponding character
Localecompare (STR1,STR2)	Compares two strings and returns a corresponding value 1/0/-1
Character method
CharAt (N)	Returns the character of the specified index position
charCodeAt (N)	Returns the character in Unicode encoding at the specified index position
Object methods
Concat (STR1...STR2)	Concatenates string arguments into a string that invokes the method
Slice (n,m)	String that returns the position of the string N to M
SUBSTRING (n,m)	String that returns the position of the string N to M
SUBSTR (n, m)	Returns the M string starting with the string n
IndexOf (str, n)	The first str is searched starting from N, and the index value of the search is returned, if not found returns-1
LastIndexOf (str, n)	Search for the last str from N, and return the search index value if not found returns-1
toLowerCase (str)	Convert all strings to lowercase
toUpperCase (str)	Convert all strings to uppercase
toLocaleLowerCase (str)	Converts the string all to lowercase, and localization
toLocaleUpperCase (str)	All strings are converted to uppercase, and localized
Match (pattern)	Returns a substring in pattern or null
Replace (pattern, replacement)	Replace pattern with replacement
Search (pattern)	Returns the start position of the pattern in a string
Split (pattern)	Returns an array of strings that are split by the specified pattern, and if the pattern is "to convert a string to a character array
Localecompare (str)	Compares two strings and returns a corresponding value 1/0/-1
HTML method
Http://www.w3school.com.cn/js/js_obj_string.asp

var flag = ' xx ' var posarr = []var STRs = ' xxooxxooxxooxxooxxooxxo '//First get string first occurrence position var firstpos = strs.indexof (flag, 0)// If not found on breakwhile (firstpos! =-1) {//First print substring and then get position Console.log (Strs.substr (Firstpos, flag.length)) Firstpos = s Trs.indexof (flag, Firstpos+flag.length)}

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