---
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>

{{Compat("api.GeolocationCoordinates.heading")}}

<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>