lovecoding
/
web0331


			
				
					
						
						
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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>
    <!-- 
        var 和 let区别
        1.var具备变量提升 let不具备变量提升
        2.var 可以重复声明变量 let不可以重复声明变量
        3.临时失效区
    -->
    <script>
        let a=1;
        console.log(a);
        // let a;
        // let a = 12;
        a = 12;
        console.log(a,'3')
        let c = 3;
        function fn() {
           let  c = 13;
        }
        fn();
        console.log(c);
    </script>
</body>
</html>