lovecoding
/
web0715


			
							12345678910111213141516171819202122232425262728293031323334353637
							<!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>
        // var a = 10;
        // var a = 20;
        // b = 10;
        // var b;

        // let a = 10;

        // var a = 10;
        // console.log(window.a);
        // let b = 20;
        // console.log(window.b);

        // const c = 30;

        // console.log("hello");


        // 新增let 定义变量使用 可修改  const 用来定义常量使用 不可修改 
        let a = 10;
        a = 20;
        console.log(a);

        const b = 20;
        b = 30;
        console.log(b);
    </script>
</body>
</html>