JavaScript 字符串的方法

let str=‘abcdefgabcd‘;

console.log(str)

//返回的是 字符串的长度

let str=‘abcdefgFADCOd‘;

let re=str.toLoewrCasr()
console.log(re)   //全部变成小写的

let str=‘abcdefgabcd‘;
let re=str.toUpperCase;
console.log(re)  //全部称为大写的

let str=‘abcdefgabcd‘;
//slice(start,end):从start索引值位置开始截取,截取到end索引值
特别注意:end截取不到
let re=str.slice(1,4)
console.log(re)

let str=‘abcdefgabcd‘;
//stubstring(start,end):从start索引值1位置开始截取,截取到end索引值

let re =str.substring(1,5)
console.log(re)   //bcde

let str=‘abcdefgabcd‘;
//substr(start,length):从start索引位置开始截取,截取到length个
let re=str.substr(1,3)
console.log(re)

let str=‘abcdefgabcd‘;
let re=str.split(‘c‘)
console.log(re)       //[‘ab‘,‘defgab‘,‘d‘]

let str=‘abcdefgabcd‘;
let re=str.indexOf(‘b‘)
console.log(re)  //(1 )

let str=‘abcdefgabcd‘;
let re=str.lastIndexOf(‘b‘)
console.log(re)  //8

let str=‘abcdefgabcd‘;
let re = str.replace(‘c‘,‘***********‘)
console.log(re)  //ab***********defgab***********d

let str=‘        abcde        fga            bcd                    ‘;
let re = str.trim(‘string‘)
console.log(re)   //abcde      fga       bcd;    

let str=‘我爱我的祖国哇哈哈‘
//查找字符串的位置
let start=str.indexOf(‘祖‘)

let re=str.substr(start,2)
consoel.log(re)