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+---
+title: Number.isNaN()
+slug: Web/JavaScript/Reference/Global_Objects/Number/isNaN
+tags:
+  - ECMAScript6
+  - Experimental
+  - JavaScript
+  - Method
+  - Método(2)
+  - Number
+translation_of: Web/JavaScript/Reference/Global_Objects/Number/isNaN
+---
+<div>{{JSRef}}</div>
+
+<p>O método <strong><code>Number.isNaN()</code></strong> determina se o valor passado é {{jsxref("Global_Objects/NaN", "NaN")}}. Esta é uma versão mais robusta que {{jsxref("Global_Objects/isNaN", "isNaN()")}}.</p>
+
+<h2 id="Sintaxe">Sintaxe</h2>
+
+<pre class="syntaxbox"><code>Number.isNaN(valor)</code></pre>
+
+<h3 id="Parâmetros">Parâmetros</h3>
+
+<dl>
+ <dt><code>valor</code></dt>
+ <dd>O valor a ser testado se é {{jsxref("Global_Objects/NaN", "NaN")}}.</dd>
+</dl>
+
+<h2 id="Descrição">Descrição</h2>
+
+<p>Due to both equality operators, {{jsxref("Operators/Comparison_Operators", "==", "#Equality")}} and {{jsxref("Operators/Comparison_Operators", "===", "#Identity")}}, evaluating to <code>false</code> when checking if {{jsxref("Global_Objects/NaN", "NaN")}} <em>is</em> {{jsxref("Global_Objects/NaN", "NaN")}}, the function <code>Number.isNaN()</code> has become necessary. This situation is unlike all other possible value comparisons in JavaScript.</p>
+
+<p>In comparison to the global {{jsxref("Global_Objects/isNaN", "isNaN()")}} function, <code>Number.isNaN()</code> doesn't suffer the problem of forcefully converting the parameter to a number. This means it is now safe to pass values that would normally convert to {{jsxref("Global_Objects/NaN", "NaN")}}, but aren't actually the same value as {{jsxref("Global_Objects/NaN", "NaN")}}. This also means that only values of the type number, that are also {{jsxref("Global_Objects/NaN", "NaN")}}, return <code>true</code>.</p>
+
+<h2 id="Exemplos">Exemplos</h2>
+
+<pre class="brush: js">Number.isNaN(NaN);        // true
+Number.isNaN(Number.NaN); // true
+Number.isNaN(0 / 0)       // true
+
+// e.g. these would have been true with global isNaN()
+Number.isNaN("NaN");      // false
+Number.isNaN(undefined);  // false
+Number.isNaN({});         // false
+Number.isNaN("blabla");   // false
+
+// These all return false
+Number.isNaN(true);
+Number.isNaN(null);
+Number.isNaN(37);
+Number.isNaN("37");
+Number.isNaN("37.37");
+Number.isNaN("");
+Number.isNaN(" ");
+</pre>
+
+<h2 id="Polyfill">Polyfill</h2>
+
+<pre class="brush: js">Number.isNaN = Number.isNaN || function(value) {
+    return typeof value === "number" &amp;&amp; isNaN(value);
+}</pre>
+
+<h2 id="Especificações">Especificações</h2>
+
+<table class="standard-table">
+ <tbody>
+  <tr>
+   <th scope="col">Especificação</th>
+   <th scope="col">Estado</th>
+   <th scope="col">Comentário</th>
+  </tr>
+  <tr>
+   <td>{{SpecName('ES6', '#sec-number.isnan', 'Number.isnan')}}</td>
+   <td>{{Spec2('ES6')}}</td>
+   <td>Definição inicial.</td>
+  </tr>
+ </tbody>
+</table>
+
+<h2 id="Compatibilidade_dos_browsers">Compatibilidade dos browsers</h2>
+
+<div>{{CompatibilityTable}}</div>
+
+<div id="compat-desktop">
+<table class="compat-table">
+ <tbody>
+  <tr>
+   <th>Funcionalidade</th>
+   <th>Chrome</th>
+   <th>Firefox (Gecko)</th>
+   <th>Internet Explorer</th>
+   <th>Opera</th>
+   <th>Safari</th>
+  </tr>
+  <tr>
+   <td>Basic support</td>
+   <td>{{CompatChrome("25")}}</td>
+   <td>{{CompatGeckoDesktop("15")}}</td>
+   <td>{{CompatNo}}</td>
+   <td>{{CompatVersionUnknown}}</td>
+   <td>9</td>
+  </tr>
+ </tbody>
+</table>
+</div>
+
+<div id="compat-mobile">
+<table class="compat-table">
+ <tbody>
+  <tr>
+   <th>Funcionalidade</th>
+   <th>Android</th>
+   <th>Chrome para Android</th>
+   <th>Firefox Mobile (Gecko)</th>
+   <th>IE Mobile</th>
+   <th>Opera Mobile</th>
+   <th>Safari Mobile</th>
+  </tr>
+  <tr>
+   <td>Basic support</td>
+   <td>{{CompatNo}}</td>
+   <td>{{CompatUnknown}}</td>
+   <td>{{CompatGeckoMobile("15")}}</td>
+   <td>{{CompatNo}}</td>
+   <td>{{CompatNo}}</td>
+   <td>iOS 9+</td>
+  </tr>
+ </tbody>
+</table>
+</div>
+
+<h2 id="Ver_também">Ver também</h2>
+
+<ul>
+ <li>{{jsxref("Global_Objects/Number", "Number")}}</li>
+ <li>{{jsxref("Global_Objects/isNaN", "isNaN()")}}</li>
+</ul>