​x
 
<!DOCTYPE html>
<html>
<body>
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<h1>JavaScript 数字</h1>
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<h2>Number.isNaN() 方法</h2>
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<p>Is "Hello" NaN?</p>
<p id="demo"></p>
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<p>Internet Explorer 11（或更早版本）不支持 Number.isNaN()。</p>
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<script>
let text = "Hello";
document.getElementById("demo").innerHTML = Number.isNaN(text);
</script>
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</body>
</html>
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