lovecoding
/
class


			
				
					
						
						
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							<!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 特点：
         * 1.不能重复声明
         * 2.不具备变量提升
         * 3.存在作用域
         * 4.块级作用域
         */
        /*
        * 变量提升：var
        */
        console.log(a1);
        // var a = 11;
        let a1 = 1;
        // let a1 = 2;

        function fn1() {
            let b = 2;
        }
        console.log(b);
        // console.log(a1);
    </script>
</body>
</html>