实例代码“Ctrl+/”提示“F11/ESC”全屏 返回 格式化 恢复 运行
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<!DOCTYPE html>
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<html>
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<head>
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    <title>Number Type Example</title>
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    <script type="text/javascript">
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        var numberObject = new Number(10);
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        var numberValue = 99;
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        //toString() using a radix
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        alert(numberObject.toString());       //"10"
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        alert(numberObject.toString(2));      //"1010"
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        alert(numberObject.toString(8));      //"12"
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        alert(numberObject.toString(10));     //"10"
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        alert(numberObject.toString(16));     //"a"
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        //toFixed()
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        alert(numberObject.toFixed(2));    //outputs "10.00"
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        numberObject = new Number(99);
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        alert(numberObject.toPrecision(1));    //"1e+2"
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        alert(numberObject.toPrecision(2));    //"99"
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        alert(numberObject.toPrecision(3));    //"99.0"
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        alert(typeof numberObject);   //object
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        alert(typeof numberValue);    //number
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        alert(numberObject instanceof Number);  //true
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        alert(numberValue instanceof Number);   //false
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    </script>
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</head>
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<body>
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</body>
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</html>