<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
// let name ="a"
// let email = name;
// console.log(email);
console.log(String.prototype);
// 1.concat():字符串拼装学习
// 方法一：加号拼接字符串
let str = "html" + ", css" + ", js";
console.log(str);
// 方法二：函数拼接字符串：便于集合化处理
str = "html".concat(", css", ", js");
console.log(str);
// 2.slice(start开始 , end结束):从子串
str = "hello php.cn";
// h-0
// e-1
// l-2
// l-3
// 0-4
// 空格-5 结果中不包括结束索引的字符
let res = str.slice(0,5);
console.log(res);
res = str.slice(0);
console.log(res);
res = str.slice(5);
console.log(res);
res = str.slice(-1);
console.log(res);
res = str.slice(-2);
console.log(res);
res = str.slice(-3);
console.log(res);
// 2.1取子串
res = str.substr (0,5);
console.log(res);
res = str.substr(-6,3);
console.log(res);
res = str.substr(-10,2);
console.log(res);
// 3.trim();删除两边的二空白字符
let psw1 = "admin123";
let input = "admin123";
console.log(psw1 === input);
psw1 = "admin123";
input = " admin123 ";
console.log(psw1 === input);
psw1 = "admin123";
input = " admin123 ";
console.log(input.length);
input = input.trim();
console.log(input);
console.log(psw1 === input);
// 字符转数组
res = str.split("");
console.log(res);
res = str.split(" ");
console.log(res);
console.log("" === " ");
console.log("html-css-js".split("-"));
let email = "[email protected]";
res = email.split("@");
console.log(res);
console.log("账号:%s",res[0]);
</script>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
// 1.push尾部添加
let arr = [];
arr.push(4);
console.log(arr);
console.log(arr.push("a"));
console.log(arr);
console.log(arr.push("b","c","d"));
console.log(arr);
// 2.pop尾部删除
console.log(arr.pop());
console.log(arr);
console.log(arr.pop());
console.log(arr);
// 3.unshift();头部添加
console.log(arr.unshift(1,2,3));
console.log(arr);
// 4.shift()头部删除
console.log(arr.shift());
console.log(arr.shift());
console.log(arr.shift());
console.log(arr);
</script>
</body>
</html>
标签：常用,console,log,res,arr,str,数组,字符串,input From： https://www.cnblogs.com/QWD7986/p/18238772