lovecoding
/
web0715


			
				
					
						
						
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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>
        // use strict 开启严格模式 且 只能写在当前作用域的最顶端
        // "use strict";
        // a = 10;
        // console.log(a);
        function foo(){
            var a = 30;
            "use strict";
            var a = 10;
            b = "hello";
            console.log(a)
        }
        a = 20;
        console.log(a);
        foo()

    </script>
</body>
</html>