diff options
Diffstat (limited to 'files/nl/web/javascript/reference/global_objects/null/index.html')
| -rw-r--r-- | files/nl/web/javascript/reference/global_objects/null/index.html | 124 |
1 files changed, 0 insertions, 124 deletions
diff --git a/files/nl/web/javascript/reference/global_objects/null/index.html b/files/nl/web/javascript/reference/global_objects/null/index.html deleted file mode 100644 index 4a5abdaa2d..0000000000 --- a/files/nl/web/javascript/reference/global_objects/null/index.html +++ /dev/null @@ -1,124 +0,0 @@ ---- -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> |
