String objects and methods in JavaScript

String Object

Two types of String objects are created

var a= "Hello";

var b=new String ("Hello");

Here's how

CharAt () Find characters in a string based on subscript

　　　　Alert (A.charat (3));//Returns a character string according to the subscript

　　　　Alert (A.charat (10));//empty, cannot find this subscript

charCodeAt () returns the character at the specified position

var a= "Hello world! Hello world! ";

var d= "This is a string";

Alert (A.charcodeat (1));//101

　　　　Alert (D.charcodeat (3));//26465

String.fromCharCode () returns a string using Unicode encoding

　　　　 Alert (String.fromCharCode (65,66,67));//

Concat () is used to concatenate one or more strings without altering the original array

var a= "Hello world! Hello world! ";

var b= "Sunshine Incense burner to give birth to purple smoke";

var c= "Less than mountain send Me Love";

Alert (A.concat (B,C))

　Search () finds the string to match, returns the first matching subscript if found, returns 1 if not found

　　　　var c= "123456789";

　　　　 Alert (C.search ("567"));//4

　　　　 Alert (C.search ("5671"));//-1

　Replace () replaces other characters with some words

　　　　 var d= "Xiao Huang is a dog, small yellow is very handsome";

　 　　 var e=d.replace ("Small yellow", "small Black");//small yellow to small black, only change for the first time

　 　 var e=d.replace (/small yellow/g, "small black")//change within the string

　 　 Alert (e);

Split () splits a string into an array of strings, and the original array is unchanged

　　　　 var a= "Hello world!";

Alert (A.split (""));

Alert (A.split ("O"));//hell, W,rld

　 IndexOf () returns the position of the first occurrence of a specified character in a string

　　　　var a= "Hello world!";

　　　　Alert (A.indexof ("O"));//4

　　　　Alert (A.indexof ("P"));//-1 No search-1

LastIndexOf () Search from backward forward

　　　　var a= "Hello world!";

Alert (A.lastindexof ("O"));//7

Match ()

var a= "Hello world! Hello world! ";

Alert (' World ')//Find the first one without looking for 5

Alert (A.match (/world/g));//Regular expression (global search)

Slice () extracts a part of a string that can be negative

var a= "Hello world! Hello world! ";

Alert (A.slice (5,13));//To the first subscript, not the second subscript

Alert (A.slice ( -15,-7));

//substring () same as slice, but does not accept negative numbers

var a= "Hello world! Hello world! ";

Alert (a.substring (4,12));

Alert (a.substring ( -3,-1));//There's nothing.

SUBSTR () intercepts the specified number of characters starting from the specified subscript

var a= "Hello world! Hello world! ";

Alert (A.SUBSTR (4,6));//intercept 6 from Subscript 4

toLowerCase () Converts a string to lowercase

var a= "Hello world! Hello world! ";

Alert (A.tolowercase ());

toUpperCase () Converts a string to uppercase

var a= "Hello world! Hello world! ";

Alert (A.touppercase ());

String objects and methods in JavaScript