Review of the day before JS

1.method of the string object (1)--Case Conversion

var str1= "ABCD"

var str2=str1.tolowercase ();//"ABCD"

var str2=str1.touppercase ();//"ABCD" var str1= "Welcome to the world of js!";

2.method of String Object (2)--Retrieval of characters

var str1= "Welcome to the world of js!";

var str2=str1.indexof ("L");//starting from 0, the result is 2;

var str3=str1.lastindexof ("L"), starting from 0, with a result of 18;

var str2 = Str 1 . Match ("World");//used to find the string

var Str 3 = Str 1 . Match ("World");//The first character position index used to match a string

Alert (str2[0]); //Results are " World " ;

alert (STR3);//The result is 15;

Method of 3.String Object (3)--substring processing

Calculate substring length

var str1= "ABcd EFGHJ "

Console.log (str1.length);//Calculation length

Console.log ( substr (str1. (1,4));//x.substr (start, length) results "Bcde"

Console.log ( substring (str1. (1,4));//x.substr (start, end) result "Bc"

var str2=str1.slice (2,4);

var str3=str1.slice (4);

var str4=str1.slice (2,-1);

var str5=str1.slice ( -3,-1);

alert (STR2);

The result is "CD"

alert (STR3);

The result is "EFGH"

alert (STR4);

The result is "CDEFG"

alert (STR5);

The result is "FG"

Review of the day before JS