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语法高亮，滚动条美化，设置页面调整

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10
docs/javascript/Reference/Global_Objects/Math/imul.html
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@@ -3,7 +3,7 @@
<h2 id="Summary" name="Summary">概述</h2>
<p>该函数返回两个参数的类C的32位整数乘法运算的运算结果.</p>
<h2 id="语法">语法</h2>
<pre class="syntaxbox"><code>Math.imul(a, b)</code></pre>
<pre><code class="language-javascript"><code>Math.imul(a, b)</code></code></pre>
<h3 id="Parameters" name="Parameters">参数</h3>
<dl>
<dt><code>a</code></dt>
@@ -14,15 +14,15 @@
<h2 id="描述">描述</h2>
<p><code>Math.imul</code>可以进行快速的,类C语义的32位整数乘法.该特性对于一些项目比如<a class="external" href="http://en.wikipedia.org/wiki/Emscripten" rel="noopener" title="http://en.wikipedia.org/wiki/Emscripten">Emscripten</a>很有用.</p>
<h2 id="例子">例子</h2>
<pre class="brush: js">Math.imul(2, 4) // 8
<pre><code class="language-javascript">Math.imul(2, 4) // 8
Math.imul(-1, 8) // -8
Math.imul(-2, -2) // 4
Math.imul(0xffffffff, 5) //-5
Math.imul(0xfffffffe, 5) //-10
</pre>
</code></pre>
<h2 id="Polyfill">Polyfill</h2>
<p>下面的JavaScript代码可以实现该函数:</p>
<pre class="brush: js">function imul(a, b)
<pre><code class="language-javascript">function imul(a, b)
{
var ah = (a &gt;&gt;&gt; 16) &amp; 0xffff;
var al = a &amp; 0xffff;
@@ -31,7 +31,7 @@ Math.imul(0xfffffffe, 5) //-10
// 右移0位可以修复高位的符号位
return (al * bl) + (((ah*bl+al*bh)&lt;&lt;16)&gt;&gt;&gt;0);
}
</pre>
</code></pre>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<p></p><div class="blockIndicator warning"><strong><a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">We're converting our compatibility data into a machine-readable JSON format</a></strong>.
This compatibility table still uses the old format,