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126 lines
19 KiB
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<article id="wikiArticle">
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<div></div>
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<p><code><strong>SharedArrayBuffer.prototype.slice()</strong></code> 方法返回一个新的<a href="Reference/Global_Objects/SharedArrayBuffer" title="SharedArrayBuffer 对象用来表示一个通用的，固定长度的原始二进制数据缓冲区，类似于 ArrayBuffer 对象，它们都可以用来在共享内存（shared memory）上创建视图。与 ArrayBuffer 不同的是，SharedArrayBuffer 不能被分离。"><code>SharedArrayBuffer</code></a> 其内容是该SharedArrayBuffer的字节从开始包含，直到结束，独占的副本。如果开始或结束是负的，它指的是从数组末尾开始的索引。此方法与 <a href="Reference/Global_Objects/Array/slice" title="The source for this interactive demo is stored in a GitHub repository. If you'd like to contribute to the interactive demo project, please clone https://github.com/mdn/interactive-examples and send us a pull request."><code>Array.prototype.slice()</code></a> 具有相同的算法。</p>
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<h2 id="Syntax">Syntax</h2>
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<pre><code class="language-javascript"><var>sab</var>.slice()
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<var>sab</var>.slice(begin)
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<var>sab</var>.slice(begin, end)</code></pre>
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<h3 id="Parameters">Parameters</h3>
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<dl>
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<dt><code>begin</code> <span class="inlineIndicator optional optionalInline">可选</span></dt>
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<dd>Zero-based index at which to begin extraction.</dd>
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<dd>A negative index can be used, indicating an offset from the end of the sequence. <code>slice(-2)</code> extracts the last two elements in the sequence.</dd>
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<dd>If <code>begin</code> is undefined, <code>slice</code> begins from index <code>0</code>.</dd>
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<dt><code>end</code> <span class="inlineIndicator optional optionalInline">可选</span></dt>
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<dd>Zero-based index <em>before</em> which to end extraction. <code>slice</code> extracts up to but not including <code>end</code>.</dd>
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<dd>For example, <code>slice(1,4)</code> extracts the second element through the fourth element (elements indexed 1, 2, and 3).</dd>
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<dd>A negative index can be used, indicating an offset from the end of the sequence. <code>slice(2,-1)</code> extracts the third element through the second-to-last element in the sequence.</dd>
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<dd>If <code>end</code> is omitted, <code>slice</code> extracts through the end of the sequence (<code>sab.byteLength</code>)<code>.</code></dd>
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</dl>
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<h3 id="Return_value">Return value</h3>
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<p>A new <a href="Reference/Global_Objects/SharedArrayBuffer" title="SharedArrayBuffer 对象用来表示一个通用的，固定长度的原始二进制数据缓冲区，类似于 ArrayBuffer 对象，它们都可以用来在共享内存（shared memory）上创建视图。与 ArrayBuffer 不同的是，SharedArrayBuffer 不能被分离。"><code>SharedArrayBuffer</code></a> containing the extracted elements.</p>
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<h2 id="Examples">Examples</h2>
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<pre><code class="language-js">var sab = new SharedArrayBuffer(1024);
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sab.slice(); // SharedArrayBuffer { byteLength: 1024 }
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sab.slice(2); // SharedArrayBuffer { byteLength: 1022 }
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sab.slice(-2); // SharedArrayBuffer { byteLength: 2 }
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sab.slice(0, 1); // SharedArrayBuffer { byteLength: 1 }
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</code></pre>
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<h2 id="Specifications">Specifications</h2>
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<table class="standard-table">
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<tbody>
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<tr>
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<th scope="col">Specification</th>
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<th scope="col">Status</th>
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<th scope="col">Comment</th>
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</tr>
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<tr>
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<td><a class="external" href="https://tc39.github.io/ecma262/#sec-sharedarraybuffer.prototype.slice" hreflang="en" lang="en" rel="noopener">ECMAScript Latest Draft (ECMA-262)<br/><small lang="zh-CN">SharedArrayBuffer.prototype.slice</small></a></td>
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<td><span class="spec-Draft">Draft</span></td>
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<td>Initial definition in ES2017.</td>
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</tr>
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</tbody>
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</table>
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<h2 id="Browser_compatibility">Browser compatibility</h2>
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<div class="hidden">The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out <a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</div>
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<p></p><div class="bc-data"><a class="bc-github-link external" href="https://github.com/mdn/browser-compat-data" rel="noopener">Update compatibility data on GitHub</a><table class="bc-table bc-table-js"><thead><tr class="bc-platforms"><td></td><th class="bc-platform-desktop" colspan="6"><span>Desktop</span></th><th class="bc-platform-mobile" colspan="7"><span>Mobile</span></th><th class="bc-platform-server" colspan="1"><span>Server</span></th></tr><tr class="bc-browsers"><td></td><th class="bc-browser-chrome"><span class="bc-head-txt-label bc-head-icon-chrome">Chrome</span></th><th class="bc-browser-edge"><span class="bc-head-txt-label bc-head-icon-edge">Edge</span></th><th class="bc-browser-firefox"><span class="bc-head-txt-label bc-head-icon-firefox">Firefox</span></th><th class="bc-browser-ie"><span class="bc-head-txt-label bc-head-icon-ie">Internet Explorer</span></th><th class="bc-browser-opera"><span class="bc-head-txt-label bc-head-icon-opera">Opera</span></th><th class="bc-browser-safari"><span class="bc-head-txt-label bc-head-icon-safari">Safari</span></th><th class="bc-browser-webview_android"><span class="bc-head-txt-label bc-head-icon-webview_android">Android webview</span></th><th class="bc-browser-chrome_android"><span class="bc-head-txt-label bc-head-icon-chrome_android">Chrome for Android</span></th><th class="bc-browser-edge_mobile"><span class="bc-head-txt-label bc-head-icon-edge_mobile">Edge Mobile</span></th><th class="bc-browser-firefox_android"><span class="bc-head-txt-label bc-head-icon-firefox_android">Firefox for Android</span></th><th class="bc-browser-opera_android"><span class="bc-head-txt-label bc-head-icon-opera_android">Opera for Android</span></th><th class="bc-browser-safari_ios"><span class="bc-head-txt-label bc-head-icon-safari_ios">Safari on iOS</span></th><th class="bc-browser-samsunginternet_android"><span class="bc-head-txt-label bc-head-icon-samsunginternet_android">Samsung Internet</span></th><th class="bc-browser-nodejs"><span class="bc-head-txt-label bc-head-icon-nodejs">Node.js</span></th></tr></thead><tbody><tr><th scope="row"><code>slice</code></th><td class="bc-supports-yes bc-browser-chrome bc-has-history"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-yes only-icon" title="Full support">
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<span>Full support</span>
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</abbr>
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68<div class="bc-icons"></div><section class="bc-history" id="sect1"><dl><dt class="bc-supports-yes bc-supports"><abbr class="bc-level-yes only-icon" title="Full support">
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<span>Full support</span>
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</abbr>
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68<div class="bc-icons"></div></dt><dd></dd><dt class="bc-supports-no bc-supports"><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>60 — 63<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Chrome disabled SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of <a class="external" href="https://www.chromium.org/Home/chromium-security/ssca" rel="noopener">speculative side-channel attacks</a>. This was a temporary removal while mitigations were put in place.</dd></dl></section></td><td class="bc-supports-no bc-browser-edge bc-has-history"><span class="bc-browser-name">Edge</span><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>16 — 17<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div><section class="bc-history" id="sect2"><dl><dt class="bc-supports-no bc-supports"><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>16 — 17<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Support was removed to mitigate <a class="external" href="https://blogs.windows.com/msedgedev/2018/01/03/speculative-execution-mitigations-microsoft-edge-internet-explorer" rel="noopener">speculative execution side-channel attacks (Windows blog)</a>.</dd></dl></section></td><td class="bc-supports-yes bc-browser-firefox bc-has-history"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
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<span>Full support</span>
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</abbr>
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57<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> <abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> </div><section class="bc-history" id="sect3"><dl><dt class="bc-supports-yes bc-supports"><abbr class="bc-level-yes only-icon" title="Full support">
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<span>Full support</span>
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</abbr>
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57<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> <abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Support was disabled by default to mitigate <a class="external" href="https://blog.mozilla.org/security/2018/01/03/mitigations-landing-new-class-timing-attack/" rel="noopener">speculative execution side-channel attacks (Mozilla Security Blog)</a>.</dd><dd><abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> From version 57: this feature is behind the <code>javascript.options.shared_memory</code> preference (needs to be set to <code>true</code>). To change preferences in Firefox, visit about:config.</dd><dt class="bc-supports-no bc-supports"><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>55 — 57<div class="bc-icons"></div></dt><dd></dd><dt class="bc-supports-no bc-supports"><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>46 — 55<div class="bc-icons"><abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> </div></dt><dd><abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> From version 46 until version 55 (exclusive): this feature is behind the <code>javascript.options.shared_memory</code> preference (needs to be set to <code>true</code>). To change preferences in Firefox, visit about:config.</dd></dl></section></td><td class="bc-supports-no bc-browser-ie"><span class="bc-browser-name">IE</span><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>
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No</td><td class="bc-supports-no bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>
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No</td><td class="bc-supports-no bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>10.1 — ?</td><td class="bc-supports-no bc-browser-webview_android bc-has-history"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>60 — 63<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div><section class="bc-history" id="sect4"><dl><dt class="bc-supports-no bc-supports"><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>60 — 63<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Chrome disabled SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of <a class="external" href="https://www.chromium.org/Home/chromium-security/ssca" rel="noopener">speculative side-channel attacks</a>. This is intended as a temporary measure until other mitigations are in place.</dd></dl></section></td><td class="bc-supports-no bc-browser-chrome_android bc-has-history"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>60 — 63<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div><section class="bc-history" id="sect5"><dl><dt class="bc-supports-no bc-supports"><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>60 — 63<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Chrome disabled SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of <a class="external" href="https://www.chromium.org/Home/chromium-security/ssca" rel="noopener">speculative side-channel attacks</a>. This is intended as a temporary measure until other mitigations are in place.</dd></dl></section></td><td class="bc-supports-unknown bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr title="Compatibility unknown; please update this.">
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?
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</abbr></td><td class="bc-supports-yes bc-browser-firefox_android bc-has-history"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
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<span>Full support</span>
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</abbr>
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57<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> <abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> </div><section class="bc-history" id="sect6"><dl><dt class="bc-supports-yes bc-supports"><abbr class="bc-level-yes only-icon" title="Full support">
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<span>Full support</span>
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</abbr>
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57<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> <abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Support was disabled by default to mitigate <a class="external" href="https://blog.mozilla.org/security/2018/01/03/mitigations-landing-new-class-timing-attack/" rel="noopener">speculative execution side-channel attacks (Mozilla Security Blog)</a>.</dd><dd><abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> From version 57: this feature is behind the <code>javascript.options.shared_memory</code> preference (needs to be set to <code>true</code>). To change preferences in Firefox, visit about:config.</dd><dt class="bc-supports-no bc-supports"><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>55 — 57<div class="bc-icons"></div></dt><dd></dd><dt class="bc-supports-no bc-supports"><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>46 — 55<div class="bc-icons"><abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> </div></dt><dd><abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> From version 46 until version 55 (exclusive): this feature is behind the <code>javascript.options.shared_memory</code> preference (needs to be set to <code>true</code>). To change preferences in Firefox, visit about:config.</dd></dl></section></td><td class="bc-supports-no bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>
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No</td><td class="bc-supports-no bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>
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No</td><td class="bc-supports-no bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr class="bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr>
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No</td><td class="bc-supports-yes bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-yes only-icon" title="Full support">
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<span>Full support</span>
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</abbr>
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8.10.0</td></tr></tbody></table><section class="bc-legend" id="sect7"><h3 class="offscreen" id="Legend">Legend</h3><dl><dt><span class="bc-supports-yes bc-supports">
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<abbr class="bc-level bc-level-yes only-icon" title="Full support">
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<span>Full support</span>
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</abbr></span></dt><dd>Full support</dd><dt><span class="bc-supports-no bc-supports">
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<abbr class="bc-level bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr></span></dt><dd>No support</dd><dt><span class="bc-supports-unknown bc-supports">
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<abbr class="bc-level bc-level-unknown only-icon" title="Compatibility unknown">
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<span>Compatibility unknown</span>
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</abbr></span></dt><dd>Compatibility unknown</dd><dt><abbr class="only-icon" title="See implementation notes."><span>See implementation notes.</span><i class="ic-footnote"></i></abbr></dt><dd>See implementation notes.</dd><dt><abbr class="only-icon" title="User must explicitly enable this feature."><span>User must explicitly enable this feature.</span><i class="ic-disabled"></i></abbr></dt><dd>User must explicitly enable this feature.</dd></dl></section></div><p></p>
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<h2 id="See_also">See also</h2>
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<ul>
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<li><a href="Reference/Global_Objects/SharedArrayBuffer" title="SharedArrayBuffer 对象用来表示一个通用的，固定长度的原始二进制数据缓冲区，类似于 ArrayBuffer 对象，它们都可以用来在共享内存（shared memory）上创建视图。与 ArrayBuffer 不同的是，SharedArrayBuffer 不能被分离。"><code>SharedArrayBuffer</code></a></li>
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<li><a href="Reference/Global_Objects/Array/slice" title="The source for this interactive demo is stored in a GitHub repository. If you'd like to contribute to the interactive demo project, please clone https://github.com/mdn/interactive-examples and send us a pull request."><code>Array.prototype.slice()</code></a></li>
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</ul>
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</article> |