---
title: Coordinates.heading
slug: Web/API/GeolocationCoordinates/heading
translation_of: Web/API/GeolocationCoordinates/heading
---
<div>{{APIRef("Geolocation API")}}</div>

<p><code><strong>Coordinates.heading</strong></code> 是個唯讀的正複數用來代表裝置前進的方向。這個數值代表你偏離北方多少度，0度代表你向著正北方，照著順時針的方向遞增(90度代表正東方，270度代表正西方)。如果{{domxref("Coordinates.speed")}} 為0度，則此值為 <code><a href="https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/NaN" title="/en-US/docs/JavaScript/Reference/Global_Objects/NaN">NaN</a></code>。如果這個裝置無法提供這個值則回傳 null。</p>

<h2 id="語法">語法</h2>

<pre class="syntaxbox"><var>heading</var> = <var>coordinates</var>.heading
</pre>

<h2 id="規格">規格</h2>

<table class="standard-table">
 <thead>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
 </thead>
 <tbody>
  <tr>
   <td>{{SpecName('Geolocation', '#heading', 'Coordinates.heading')}}</td>
   <td>{{Spec2('Geolocation')}}</td>
   <td>Initial specification.</td>
  </tr>
 </tbody>
</table>

<h2 id="瀏覽器的相容性">瀏覽器的相容性</h2>

<p>{{CompatibilityTable}}</p>

<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>5</td>
   <td>{{CompatGeckoDesktop("1.9.1")}}</td>
   <td>9</td>
   <td>10.60<br>
    {{CompatNo}} 15.0<br>
    16.0</td>
   <td>5</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>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatGeckoMobile("4")}}</td>
   <td>{{CompatUnknown}}</td>
   <td>10.60</td>
   <td>{{CompatUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="請參考">請參考</h2>

<ul>
 <li><a href="/en-US/docs/WebAPI/Using_geolocation">Using geolocation</a></li>
 <li>屬於 {{domxref("Coordinates")}} 介面。</li>
</ul>