in js/controllers/slidecontent.js [275:358]
startEmbeddedContent( element ) {
if( element && !this.Reveal.isSpeakerNotes() ) {
// Restart GIFs
queryAll( element, 'img[src$=".gif"]' ).forEach( el => {
// Setting the same unchanged source like this was confirmed
// to work in Chrome, FF & Safari
el.setAttribute( 'src', el.getAttribute( 'src' ) );
} );
// HTML5 media elements
queryAll( element, 'video, audio' ).forEach( el => {
if( closest( el, '.fragment' ) && !closest( el, '.fragment.visible' ) ) {
return;
}
// Prefer an explicit global autoplay setting
let autoplay = this.Reveal.getConfig().autoPlayMedia;
// If no global setting is available, fall back on the element's
// own autoplay setting
if( typeof autoplay !== 'boolean' ) {
autoplay = el.hasAttribute( 'data-autoplay' ) || !!closest( el, '.slide-background' );
}
if( autoplay && typeof el.play === 'function' ) {
// If the media is ready, start playback
if( el.readyState > 1 ) {
this.startEmbeddedMedia( { target: el } );
}
// Mobile devices never fire a loaded event so instead
// of waiting, we initiate playback
else if( isMobile ) {
let promise = el.play();
// If autoplay does not work, ensure that the controls are visible so
// that the viewer can start the media on their own
if( promise && typeof promise.catch === 'function' && el.controls === false ) {
promise.catch( () => {
el.controls = true;
// Once the video does start playing, hide the controls again
el.addEventListener( 'play', () => {
el.controls = false;
} );
} );
}
}
// If the media isn't loaded, wait before playing
else {
el.removeEventListener( 'loadeddata', this.startEmbeddedMedia ); // remove first to avoid dupes
el.addEventListener( 'loadeddata', this.startEmbeddedMedia );
}
}
} );
// Normal iframes
queryAll( element, 'iframe[src]' ).forEach( el => {
if( closest( el, '.fragment' ) && !closest( el, '.fragment.visible' ) ) {
return;
}
this.startEmbeddedIframe( { target: el } );
} );
// Lazy loading iframes
queryAll( element, 'iframe[data-src]' ).forEach( el => {
if( closest( el, '.fragment' ) && !closest( el, '.fragment.visible' ) ) {
return;
}
if( el.getAttribute( 'src' ) !== el.getAttribute( 'data-src' ) ) {
el.removeEventListener( 'load', this.startEmbeddedIframe ); // remove first to avoid dupes
el.addEventListener( 'load', this.startEmbeddedIframe );
el.setAttribute( 'src', el.getAttribute( 'data-src' ) );
}
} );
}
}