NaN

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	<script>
		console.log(NaN == NaN);  // false
		console.log(isNaN(NaN));  // true
	</script>
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  NaN 和 NaN在任何情况下都不相等;

  判断是否为NaN只有用系统内置函数 : isNaN() ;

author:Lik
Endeavoring to powerless, struggling to move yourself.
原文地址:https://www.cnblogs.com/likwin/p/7141839.html