DeviceOrientation API

<div class="dln" itemprop="articleBody"><div class="shdw top"> </div><p><a class="URI" href="https://developer.mozilla.org/ja/docs/Web/API/Device_orientation_events/Detecting_device_orientation" target="_blank" rel="noopener nofollow ugc">https://developer.mozilla.org/ja/docs/Web/API/Device_orientation_events/Detecting_device_orientation</a>
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『端末の方向の検出 - Web API | MDN』

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t_wの輪郭

DeviceOrientation API

『端末の方向の検出 - Web API | MDN』

『Javascriptでコンパスを作ってAndroid、iPhoneが向いている方角を特定 – One IT Thing』