<!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> /** * const 特点： * 1.具备块级作用域 * 2.一般用于声明常量 * 3.不能重复赋值 */ const PI = 3.14159; // const aa = 12; // const aa = 14; </script> </body> </html>
