in js/reveal.js [3563:3590]
toArray( fragments ).forEach( function( element, i ) {
if( element.hasAttribute( 'data-fragment-index' ) ) {
i = parseInt( element.getAttribute( 'data-fragment-index' ), 10 );
}
// Visible fragments
if( i <= index ) {
if( !element.classList.contains( 'visible' ) ) fragmentsShown.push( element );
element.classList.add( 'visible' );
element.classList.remove( 'current-fragment' );
// Announce the fragments one by one to the Screen Reader
dom.statusDiv.textContent = element.textContent;
if( i === index ) {
element.classList.add( 'current-fragment' );
}
}
// Hidden fragments
else {
if( element.classList.contains( 'visible' ) ) fragmentsHidden.push( element );
element.classList.remove( 'visible' );
element.classList.remove( 'current-fragment' );
}
} );