javascript Number.isNaN 在 IE 中不存在
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Number.isNaN doesn't exist in IE
提问by impulsgraw
Why does not IE support the Number.isNaNfunction? I can't use simple isNan instead of Number.isNaN 'cause these functions are different! For example:
为什么 IE 不支持Number.isNaN函数？我不能使用简单的 isNan 而不是 Number.isNaN ，因为这些函数是不同的！例如：
Number.isNaN("abacada") != isNaN("abacada") //false != true
I need to abstract string and number and check, is some var really contains NaN(I mean NaN constant, but not-a-number value like strings).
我需要抽象字符串和数字并检查一些 var 是否真的包含NaN（我的意思是 NaN 常量，但不是像字符串那样的数字值）。
someobj.someopt = "blah"/0;
someobj.someopt2 = "blah";
someobj.someopt3 = 150;
for(a in someobj) if(Number.isNaN(someobj[a])) alert('!');
That code should show alert for 1 time. But if I will change Number.isNaN to isNaN, it will alert 2 times. There are differences.
该代码应显示警报 1 次。但是如果我将 Number.isNaN 更改为 isNaN，它会发出 2 次警报。有差异。
May be there is some alternative function exists?
可能存在一些替代功能吗？
回答by ruakh
Why does not IE support the Number.isNaNfunction?
为什么 IE 不支持Number.isNaN函数？
That's rather off-topic for Stack Overflow, but according to the MDN page for Number.isNaN, it's not defined in any standard — it's only in the draft spec for ECMAScript 6 — and Internet Explorer is not the only browser that doesn't support it.
这对于 Stack Overflow 来说是相当离题的，但根据的 MDN 页面Number.isNaN，它没有在任何标准中定义——它只在 ECMAScript 6 的草案规范中——并且 Internet Explorer 不是唯一不支持它的浏览器。
May be there is some alternative function exists?
可能存在一些替代功能吗？
Not really, but you can easily define one:
并非如此，但您可以轻松定义一个：
function myIsNaN(o) {
return typeof(o) === 'number' && isNaN(o);
}
or if you prefer:
或者，如果您更喜欢：
function myIsNaN(o) {
return o !== o;
}
回答by ?ukasz Wojtanowski
You need use isNaN without "Number." Like this:
您需要使用不带“数字”的 isNaN。像这样：
for(a in someobj) if(isNaN(someobj[a])) alert('!');
for(a in someobj) if(isNaN(someobj[a])) alert('!');
This also work fine for chrome.
这也适用于铬。
You can find more on microsoft site https://docs.microsoft.com/en-us/scripting/javascript/reference/isnan-function-javascript
您可以在微软网站https://docs.microsoft.com/en-us/scripting/javascript/reference/isnan-function-javascript上找到更多信息
