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@@ -0,0 +1,34 @@
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+<!DOCTYPE html>
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+<html lang="en">
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+<head>
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+ <meta charset="UTF-8">
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+ <meta name="viewport" content="width=device-width, initial-scale=1.0">
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+ <title>Document</title>
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+</head>
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+<body>
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+ <script>
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+ console.log(Math.PI);
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+
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+ var num = 10.1;
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+ // 四舍五入
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+ console.log(Math.round(num));
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+ // 向下取整
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+ console.log(Math.floor(num));
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+ // 向上取整
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+ console.log(Math.ceil(num));
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+
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+
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+ var num2 = "8.2";
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+ // 字符串拼接
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+ console.log(num2 + 2);
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+
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+ // 字符串转数字 只能转换成整型 取整数部分
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+ num2 = parseInt(num2)
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+ console.log(num2 + 2);
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+
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+ var num3 = "8.2";
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+ num3 = parseFloat(num3);
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+ console.log(num3 + 2);
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+ </script>
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+</body>
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+</html>
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