study/uTools-Manuals
1
0
Fork 0
mirror of https://github.com/fofolee/uTools-Manuals.git synced 2026-03-03 19:47:13 +08:00
Code Issues Packages Projects Releases Wiki Activity

语法高亮，滚动条美化，设置页面调整

Browse Source
This commit is contained in:
fofolee
2019-04-19 02:41:09 +08:00
parent 1e8f76c000
commit 359d29ee0b
1590 changed files with 12328 additions and 11441 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
docs/javascript/Reference/Global_Objects/Math/sign.html
View File

@@ -3,7 +3,7 @@
<div> </div>
<p><strong><code>Math.sign()</code></strong> 函数返回一个数字的符号, 指示数字是正数，负数还是零。</p>
<h2 id="Syntax" name="Syntax">语法</h2>
<pre class="syntaxbox"><code>Math.sign(<em>x</em>);</code></pre>
<pre><code class="language-javascript"><code>Math.sign(<em>x</em>);</code></code></pre>
<h3 id="Parameters" name="Parameters">参数</h3>
<dl>
<dt><code>x</code></dt>
@@ -16,7 +16,7 @@
<p>传入该函数的参数会被<strong>隐式转换</strong>成数字类型。</p>
<h2 id="Examples" name="Examples">示例</h2>
<h3 id="使用Math.sign()">使用Math.sign()</h3>
<pre class="brush:js">Math.sign(3); // 1
<pre><code class="language-js">Math.sign(3); // 1
Math.sign(-3); // -1
Math.sign("-3"); // -1
Math.sign(0); // 0
@@ -24,14 +24,14 @@ Math.sign(-0); // -0
Math.sign(NaN); // NaN
Math.sign("foo"); // NaN
Math.sign(); // NaN
</pre>
</code></pre>
<h2 id="Compatibility" name="Compatibility">Polyfill</h2>
<pre class="brush: js language-js"><code class="language-js"><span class="keyword token">function</span> <span class="function token">sign<span class="punctuation token">(</span></span>x<span class="punctuation token">)</span> <span class="punctuation token">{</span>
<pre><code class="language-js language-js"><code class="language-js"><span class="keyword token">function</span> <span class="function token">sign<span class="punctuation token">(</span></span>x<span class="punctuation token">)</span> <span class="punctuation token">{</span>
x <span class="operator token">=</span> <span class="operator token">+</span>x<span class="comment token"> ;// convert to a number
</span> <span class="keyword token">if</span> <span class="punctuation token">(</span>x <span class="operator token">===</span> <span class="number token">0</span> <span class="operator token">||</span> <span class="function token">isNaN<span class="punctuation token">(</span></span>x<span class="punctuation token">)</span><span class="punctuation token">)</span>
<span class="keyword token">return</span> x;
<span class="keyword token">return</span> x <span class="operator token">&gt;</span> <span class="number token">0</span> <span class="operator token">?</span> <span class="number token">1</span> <span class="punctuation token">:</span> <span class="operator token">-</span><span class="number token">1;</span>
<span class="punctuation token">}</span></code></pre>
<span class="punctuation token">}</span></code></code></pre>
<p> </p>
<pre><code>if (!Math.sign) {
Math.sign = function(x) {
@@ -46,7 +46,7 @@ Math.sign(); // NaN
}
return x &gt; 0 ? 1 : -1;
};
}</code></pre>
}</code></code></pre>
<p> </p>
<h2 id="规范">规范</h2>
<table class="standard-table">