files/pt-br/web/javascript/reference/global_objects/math/abs/index.html


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---
title: Math.abs()
slug: Web/JavaScript/Reference/Global_Objects/Math/abs
translation_of: Web/JavaScript/Reference/Global_Objects/Math/abs
---
<div>{{JSRef("Global_Objects", "Math")}}</div>

<h2 id="Summary" name="Summary">Sumário</h2>

<p>A função <code><strong>Math.abs(x)</strong></code> retorna o valor absoluto de um número "x", tal qual:</p>

<p><math display="block"><semantics><mrow><mstyle mathvariant="monospace"><mrow><mo lspace="0em" rspace="thinmathspace">Math.abs</mo><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></mrow></mstyle><mo>=</mo><mrow><mo stretchy="false">|</mo><mi>x</mi><mo stretchy="false">|</mo></mrow><mo>=</mo><mrow><mo>{</mo><mtable columnalign="left left"><mtr><mtd><mi>x</mi></mtd><mtd><mtext>if</mtext><mspace width="1em"></mspace><mi>x</mi><mo>&gt;</mo><mn>0</mn></mtd></mtr><mtr><mtd><mi>0</mi></mtd><mtd><mtext>if</mtext><mspace width="1em"></mspace><mi>x</mi><mo>=</mo><mn>0</mn></mtd></mtr><mtr><mtd><mo>-</mo><mi>x</mi></mtd><mtd><mtext>if</mtext><mspace width="1em"></mspace><mi>x</mi><mo>&lt;</mo><mn>0</mn></mtd></mtr></mtable></mrow></mrow><annotation encoding="TeX">{\mathtt{\operatorname{Math.abs}(x)}} = {|x|} = \begin{cases} x &amp; \text{if} \quad x \geq 0 \\ -x &amp; \text{if} \quad x &lt; 0 \end{cases} </annotation></semantics></math></p>

<h2 id="Syntax" name="Syntax">Sintaxe</h2>

<pre class="syntaxbox">var abs = Math.abs(<em>x</em>);</pre>

<h3 id="Parameters" name="Parameters">Parâmetros</h3>

<dl>
 <dt><code>x</code></dt>
 <dd>Um número.</dd>
</dl>

<h3 id="Valor_de_Retorno">Valor de Retorno</h3>

<p>O valor absoluto do número passado</p>

<h2 id="Description" name="Description">Descrição.</h2>

<p>Por <code>abs</code> ser um método estático de <code>Math</code>, você sempre o usará como <code>Math.abs() </code>ao ínves de usar como método de um objeto <code>Math</code> criado por você. (<code>Math</code> não é um construtor);</p>

<h2 id="Examples" name="Examples">Exemplos</h2>

<h3 id="Example:_Math.abs_behavior" name="Example:_Math.abs_behavior">Comportamento de <code>Math.abs()</code></h3>

<p>Passando um string não-numérica ou variável indefinida/vazia retorna <code>NaN</code>. Passando null retorna 0.</p>

<pre class="brush: js">Math.abs('-1');     // 1
Math.abs(-2);       // 2
Math.abs(null);     // 0
Math.abs('');       // 0
Math.abs([]);       // 0
Math.abs([2]);      // 2
Math.abs([1,2]);    // NaN
Math.abs({});       // NaN
Math.abs('string'); // NaN
Math.abs();         // NaN</pre>

<h2 id="Especificações">Especificações</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
  <tr>
   <td>{{SpecName('ES1')}}</td>
   <td>{{Spec2('ES1')}}</td>
   <td>Initial definition. Implemented in JavaScript 1.0.</td>
  </tr>
  <tr>
   <td>{{SpecName('ES5.1', '#sec-15.8.2.1', 'Math.abs')}}</td>
   <td>{{Spec2('ES5.1')}}</td>
   <td> </td>
  </tr>
  <tr>
   <td>{{SpecName('ES6', '#sec-math.abs', 'Math.abs')}}</td>
   <td>{{Spec2('ES6')}}</td>
   <td> </td>
  </tr>
  <tr>
   <td>{{SpecName('ESDraft', '#sec-math.abs', 'Math.abs')}}</td>
   <td>{{Spec2('ESDraft')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Compatibilidade com navegadores</h2>

<p>{{ CompatibilityTable() }}</p>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</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>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Chrome for 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>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="See_also" name="See_also">Veja Também</h2>

<ul>
 <li>{{jsxref("Math.ceil()")}}</li>
 <li>{{jsxref("Math.floor()")}}</li>
 <li>{{jsxref("Math.round()")}}</li>
 <li>{{jsxref("Math.sign()")}}</li>
 <li>{{jsxref("Math.trunc()")}}</li>
</ul>