initial commit

1 files changed, 74 insertions, 0 deletions

diff --git a/files/zh-cn/web/css/frequency/index.html b/files/zh-cn/web/css/frequency/index.html
new file mode 100644
index 0000000000..f230c49052
--- /dev/null
+++ b/files/zh-cn/web/css/frequency/index.html
@@ -0,0 +1,74 @@
+---
+title: <frequency>
+slug: Web/CSS/frequency
+tags:
+  - CSS
+  - Web
+  - 参考
+translation_of: Web/CSS/frequency
+---
+<div>{{CSSRef}}</div>
+
+<p><span><code>&lt;frequency&gt;</code> <a href="/en-US/docs/Web/CSS">CSS</a></span>数据类型表示频率维度，例如语音的音高。目前它未在任何 CSS 属性中被使用。</p>
+
+<h2 id="语法">语法</h2>
+
+<p>The <code>&lt;frequency&gt;</code> data type consists of a {{cssxref("&lt;number&gt;")}} followed by one of the units listed below. As with all CSS dimensions, there is no space between the unit literal and the number.</p>
+
+<h3 id="单位">单位</h3>
+
+<p>可以使用以下单位：</p>
+
+<dl>
+ <dt><code><a id="Hz" name="Hz">Hz</a></code></dt>
+ <dd>表示以赫兹（hertz）为单位的频率。例如：<code>0Hz</code>、<code>1500Hz</code>、<code>10000Hz</code>。</dd>
+ <dt><code><a id="kHz" name="kHz">kHz</a></code></dt>
+ <dd>表示以千赫兹（kilohertz）为单位的频率。例如：<code>0kHz</code>、<code>1.5kHz</code>、<code>10kHz</code>。</dd>
+</dl>
+
+<div class="note">
+<p><strong>Note:</strong> Although the number <code>0</code> is always the same regardless of unit, the unit may not be omitted. In other words, <code>0</code> is invalid and does not represent <code>0Hz</code> or <code>0kHz</code>. Though the units are case-insensitive, it is good practice to use a capital "H" for <code>Hz</code> and <code>kHz</code>, as specified in the <a class="external" href="https://en.wikipedia.org/wiki/International_System_of_Units">SI</a>.</p>
+</div>
+
+<h2 id="示例">示例</h2>
+
+<pre>12Hz     Positive integer
+4.3Hz    Non-integer
+14KhZ    The unit is case-insensitive, though non-SI capitalization is not recommended.
++0Hz     Zero, with a leading + and a unit
+-0kHz    Zero, with a leading - and a unit</pre>
+
+<h3 id="Invalid_frequency_values">Invalid frequency values</h3>
+
+<pre class="example-bad">12.0     This is a &lt;number&gt;, not an &lt;frequency&gt;, because it is missing a unit.
+7 Hz     No space is allowed between the number and the unit.
+0        Although unitless zero is an allowable &lt;length&gt;, it's an invalid &lt;frequency&gt;.</pre>
+
+<h2 id="规范">规范</h2>
+
+<table class="standard-table">
+ <thead>
+  <tr>
+   <th scope="col">规范</th>
+   <th scope="col">状态</th>
+   <th scope="col">备注</th>
+  </tr>
+ </thead>
+ <tbody>
+  <tr>
+   <td>{{SpecName('CSS3 Values', '#frequency', '&lt;frequency&gt;')}}</td>
+   <td>{{Spec2('CSS3 Values')}}</td>
+   <td>Initial definition</td>
+  </tr>
+ </tbody>
+</table>
+
+<div class="note">
+<p><strong>Note:</strong> This data type was initially introduced in <a class="external" href="https://www.w3.org/TR/CSS2/aural.html#q19.0" title="http://www.w3.org/TR/CSS2/">CSS Level 2</a> for the now-obsolete <a href="/en-US/docs/Web/CSS/@media/aural" title="aural">aural</a> <a href="/en-US/docs/Web/CSS/@media#Media_types">media type</a>, where it was used to define the pitch of the voice. However, the <code>&lt;frequency&gt;</code> data type has been reintroduced in CSS3, though no CSS property is using it at the moment.</p>
+</div>
+
+<h2 id="浏览器兼容性">浏览器兼容性</h2>
+
+
+
+<p>{{Compat("css.types.frequency")}}</p>