The code below was tested on iPhone, iPad (iOS13), Safari (Catalina). It was able to autoplay the YouTube video on all devices. Make sure the video is muted and the playsinline parameter is on. Those are the magic parameters that make it work.
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=2.0, minimum-scale=1.0, user-scalable=yes">
</head>
<body>
<!-- 1. The <iframe> (video player) will replace this <div> tag. -->
<div id="player"></div>
<script>
// 2. This code loads the IFrame Player API code asynchronously.
var tag = document.createElement('script');
tag.src = "https://www.youtube.com/iframe_api";
var firstScriptTag = document.getElementsByTagName('script')[0];
firstScriptTag.parentNode.insertBefore(tag, firstScriptTag);
// 3. This function creates an <iframe> (and YouTube player)
// after the API code downloads.
var player;
function onYouTubeIframeAPIReady() {
player = new YT.Player('player', {
width: '100%',
videoId: 'osz5tVY97dQ',
playerVars: { 'autoplay': 1, 'playsinline': 1 },
events: {
'onReady': onPlayerReady
}
});
}
// 4. The API will call this function when the video player is ready.
function onPlayerReady(event) {
event.target.mute();
event.target.playVideo();
}
</script>
</body>
</html>