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---
title: 'null'
slug: Web/JavaScript/Reference/Global_Objects/null
translation_of: Web/JavaScript/Reference/Global_Objects/null
---
<div>{{jsSidebar("Objects")}}</div>
<p>De waarde <code>null</code> representeert het moedwillig weglaten, of de bedoelde afwezigheid van welk object of waarde dan ook. Het is een van JavaScript's {{Glossary("Primitive", "primitive values")}}.</p>
<h2 id="Syntax">Syntax</h2>
<pre class="syntaxbox"><code>null </code></pre>
<h2 id="Beschrijving">Beschrijving</h2>
<p>De waarde <code>null</code> wordt letterlijk geschreven als <code>null</code> (het is geen idenfifier voor een eigenschap van de global object zoals {{jsxref("Global_Objects/undefined","undefined")}} wel kan zijn). In APIs, wordt <code>null</code> vaak verkregen op plekken waar een object mag worden verwacht, maar waar tegelijk geen object relevant is . Wanneer op null of undefined wordt gecontroleerd, wees dan bewust van de <a href="/en-US/docs/Web/JavaScript/Reference/Operators/Comparison_Operators">verschillen tussen equality (==) en identity (===) operators</a> (type-conversie wordt via de eerste bereikt).</p>
<pre class="brush: js">// foo does not exist. It is not defined and has never been initialized:
> foo
"ReferenceError: foo is not defined"
// foo is known to exist now but it has no type or value:
> var foo = null; foo
"null"
</pre>
<h3 id="Verschil_tussen_null_en_undefined">Verschil tussen <code>null</code> en <code> undefined</code></h3>
<pre class="brush: js">typeof null // object (bug in ECMAScript, should be null)
typeof undefined // undefined
null === undefined // false
null == undefined // true
</pre>
<h2 id="Specificaties">Specificaties</h2>
<table class="standard-table">
<tbody>
<tr>
<th scope="col">Specificatie</th>
<th scope="col">Status</th>
<th scope="col">Commentaar</th>
</tr>
<tr>
<td>{{SpecName('ES1')}}</td>
<td>{{Spec2('ES1')}}</td>
<td>Initial definition.</td>
</tr>
<tr>
<td>{{SpecName('ES5.1', '#sec-4.3.11', 'null value')}}</td>
<td>{{Spec2('ES5.1')}}</td>
<td> </td>
</tr>
<tr>
<td>{{SpecName('ES6', '#sec-null-value', 'null value')}}</td>
<td>{{Spec2('ES6')}}</td>
<td> </td>
</tr>
<tr>
<td>{{SpecName('ESDraft', '#sec-null-value', 'null value')}}</td>
<td>{{Spec2('ESDraft')}}</td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="Browser_compatibiliteit">Browser compatibiliteit</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="Zie_ook">Zie ook</h2>
<ul>
<li>{{jsxref("undefined")}}</li>
<li>{{jsxref("NaN")}}</li>
</ul>
|
