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// 变量 letlet a = 'kira';console.log(a);// 常量const APP_KIRA= 'PHP中网';console.log(APP_KIRA);
//1.块作用域{//代码段/代码块let a = 'php中文网';console.log(a);}// 函数作用域function chufa(a , b){// 函数内声明的变量 私有变量/局部变量let res = a / b;return res;}console.log(chufa(10 , 40));
et $user = 111;console.log($user);let user_name = 'my name is 蛇形命名法';console.log(user_name);let UserName = 'my name is 大驼峰';console.log(UserName);const APP_USER = 'KIRA管理员';console.log(APP_USER);
function sum(a , b){return a + b;}console.log(sum(10 ,20));let jianfa = function(a , b){return a - b ;}console.log(jianfa(10 ,20));getChengFa = (a , b) =>{return a * b ;};console.log(getChengFa(10 ,20));
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>JS变量/常量/作用域之间的关系</title></head><body>1. 变量,常量的声明与初始化2. 作用域3. 写出合法标识符的基本规则,并实例演示4. 实例演示最常用 的三种函数类型<script>// 1. 实例演示变量,常量的声明与初始化,使用方法// 变量 letlet a = 'kira';console.log(a);// 常量const APP_KIRA= 'PHP中网';console.log(APP_KIRA);// 作用域//1.块作用域{let a = 'php中文网';console.log(a);}// 函数作用域function chufa(a , b){let res = a / b;return res;}console.log(chufa(10 , 40));// 标识符书写基本规则let $user =111;console.log($user);let user_name = 'my name is 蛇形命名法';console.log(user_name);let UserName = 'my name is 大驼峰';console.log(UserName);const APP_USER = 'KIRA管理员';console.log(APP_USER);// JS函数写法如下function sum(a , b){return a + b;}console.log(sum(10 ,20));let jianfa = function(a , b){return a - b ;}console.log(jianfa(10 ,20));getChengFa = (a , b) =>{return a * b ;};console.log(getChengFa(10 ,20));</script></body>
