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---
title: Object
slug: Web/JavaScript/Reference/Global_Objects/Object
tags:
- Constructor
- JavaScript
- NeedsTranslation
- Object
- TopicStub
translation_of: Web/JavaScript/Reference/Global_Objects/Object
---
<div>{{JSRef}}</div>
<p><code><strong>Object</strong></code> 建構式可用於建立物件包裝（object wrapper）。</p>
<h2 id="語法">語法</h2>
<pre class="syntaxbox">// Object initialiser or literal
{ [ <var>nameValuePair1</var>[, <var>nameValuePair2</var>[, ...<var>nameValuePairN</var>] ] ] }
// Called as a constructor
new Object([<var>value</var>])</pre>
<h3 id="參數">參數</h3>
<dl>
<dt><code>nameValuePair1, nameValuePair2, ... nameValuePair<em>N</em></code></dt>
<dd>Pairs of names (strings) and values (any value) where the name is separated from the value by a colon.</dd>
<dt><code>value</code></dt>
<dd>任意值。</dd>
</dl>
<h2 id="描述">描述</h2>
<p>The <code>Object</code> constructor creates an object wrapper for the given value. If the value is {{jsxref("null")}} or {{jsxref("undefined")}}, it will create and return an empty object, otherwise, it will return an object of a Type that corresponds to the given value. If the value is an object already, it will return the value.</p>
<p>When called in a non-constructor context, <code>Object</code> behaves identically to <code>new Object()</code>.</p>
<p>也可以參考 <a href="/zh-TW/docs/Web/JavaScript/Reference/Operators/Object_initializer">object initializer / literal syntax</a>.</p>
<h2 id="Object_建構式屬性"><code>Object</code> 建構式屬性</h2>
<dl>
<dt><code>Object.length</code></dt>
<dd>Has a value of 1.</dd>
<dt>{{jsxref("Object.prototype")}}</dt>
<dd>Allows the addition of properties to all objects of type Object.</dd>
</dl>
<h2 id="Object_建構式方法"><code>Object</code> 建構式方法</h2>
<dl>
<dt>{{jsxref("Object.assign()")}}</dt>
<dd>Creates a new object by copying the values of all enumerable own properties from one or more source objects to a target object.</dd>
<dt>{{jsxref("Object.create()")}}</dt>
<dd>Creates a new object with the specified prototype object and properties.</dd>
<dt>{{jsxref("Object.defineProperty()")}}</dt>
<dd>Adds the named property described by a given descriptor to an object.</dd>
<dt>{{jsxref("Object.defineProperties()")}}</dt>
<dd>Adds the named properties described by the given descriptors to an object.</dd>
<dt>{{jsxref("Object.entries()")}} {{experimental_inline}}</dt>
<dd>Returns an array of a given object's own enumerable property <code>[key, value]</code> pairs.</dd>
<dt>{{jsxref("Object.freeze()")}}</dt>
<dd>Freezes an object: other code can't delete or change any properties.</dd>
<dt>{{jsxref("Object.getOwnPropertyDescriptor()")}}</dt>
<dd>Returns a property descriptor for a named property on an object.</dd>
<dt>{{jsxref("Object.getOwnPropertyDescriptors()")}}</dt>
<dd>Returns an object containing all own property descriptors for an object.</dd>
<dt>{{jsxref("Object.getOwnPropertyNames()")}}</dt>
<dd>Returns an array containing the names of all of the given object's <strong>own</strong> enumerable and non-enumerable properties.</dd>
<dt>{{jsxref("Object.getOwnPropertySymbols()")}}</dt>
<dd>Returns an array of all symbol properties found directly upon a given object.</dd>
<dt>{{jsxref("Object.getPrototypeOf()")}}</dt>
<dd>Returns the prototype of the specified object.</dd>
<dt>{{jsxref("Object.is()")}}</dt>
<dd>Compares if two values are distinguishable (ie. the same)</dd>
<dt>{{jsxref("Object.isExtensible()")}}</dt>
<dd>Determines if extending of an object is allowed.</dd>
<dt>{{jsxref("Object.isFrozen()")}}</dt>
<dd>Determines if an object was frozen.</dd>
<dt>{{jsxref("Object.isSealed()")}}</dt>
<dd>Determines if an object is sealed.</dd>
<dt>{{jsxref("Object.keys()")}}</dt>
<dd>Returns an array containing the names of all of the given object's <strong>own</strong> enumerable properties.</dd>
<dt>{{jsxref("Object.preventExtensions()")}}</dt>
<dd>Prevents any extensions of an object.</dd>
<dt>{{jsxref("Object.seal()")}}</dt>
<dd>Prevents other code from deleting properties of an object.</dd>
<dt>{{jsxref("Object.setPrototypeOf()")}}</dt>
<dd>Sets the prototype (i.e., the internal <code>[[Prototype]]</code> property)</dd>
<dt>{{jsxref("Object.values()")}} {{experimental_inline}}</dt>
<dd>Returns an array of a given object's own enumerable values.</dd>
</dl>
<h2 id="Object_物件實體與_Object_原型物件"><code>Object</code> 物件實體與 <code>Object</code> 原型物件</h2>
<p>All objects in JavaScript are descended from <code>Object</code>; all objects inherit methods and properties from {{jsxref("Object.prototype")}}, although they may be overridden. For example, other constructors' prototypes override the <code>constructor</code> property and provide their own <code>toString()</code> methods. Changes to the <code>Object</code> prototype object are propagated to all objects unless the properties and methods subject to those changes are overridden further along the prototype chain.</p>
<h3 id="屬性">屬性</h3>
<div>{{page('/zh-TW/docs/Web/JavaScript/Reference/Global_Objects/Object/prototype', '屬性') }}</div>
<h3 id="方法">方法</h3>
<div>{{page('/zh-TW/docs/Web/JavaScript/Reference/Global_Objects/Object/prototype', '方法') }}</div>
<h2 id="範例">範例</h2>
<h3 id="Using_Object_given_undefined_and_null_types">Using <code>Object</code> given <code>undefined</code> and <code>null</code> types</h3>
<p>下面例子儲存一個空物件至變數o</p>
<pre class="brush: js">var o = new Object();
</pre>
<pre class="brush: js">var o = new Object(undefined);
</pre>
<pre class="brush: js">var o = new Object(null);
</pre>
<h3 id="Using_Object_to_create_Boolean_objects">Using <code>Object</code> to create <code>Boolean</code> objects</h3>
<p>下面例子儲存 {{jsxref("Boolean")}} 物件在 <code>o</code>:</p>
<pre class="brush: js">// equivalent to o = new Boolean(true);
var o = new Object(true);
</pre>
<pre class="brush: js">// equivalent to o = new Boolean(false);
var o = new Object(Boolean());
</pre>
<h2 id="規範">規範</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-15.2', 'Object')}}</td>
<td>{{Spec2('ES5.1')}}</td>
<td></td>
</tr>
<tr>
<td>{{SpecName('ES6', '#sec-object-objects', 'Object')}}</td>
<td>{{Spec2('ES6')}}</td>
<td>Added Object.assign, Object.getOwnPropertySymbols, Object.setPrototypeOf, Object.is</td>
</tr>
<tr>
<td>{{SpecName('ESDraft', '#sec-object-objects', 'Object')}}</td>
<td>{{Spec2('ESDraft')}}</td>
<td>Added Object.entries, Object.values and Object.getOwnPropertyDescriptors.</td>
</tr>
</tbody>
</table>
<h2 id="瀏覽器相容性">瀏覽器相容性</h2>
<div>{{CompatibilityTable}}</div>
<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="參見">參見</h2>
<ul>
<li><a href="/zh-TW/docs/Web/JavaScript/Reference/Operators/Object_initializer">Object initializer</a></li>
</ul>
|
