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merge and tweak screen reader support #854

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This commit is contained in:
Hakim El Hattab 2014-06-09 11:20:34 +02:00
commit 943b6ef37e
1 changed files with 37 additions and 0 deletions
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37
js/reveal.js
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@ -432,6 +432,8 @@
dom.controls = document.querySelector( '.reveal .controls' );
dom.theme = document.querySelector( '#theme' );
dom.wrapper.setAttribute( 'role', 'application' );
// There can be multiple instances of controls throughout the page
dom.controlsLeft = toArray( document.querySelectorAll( '.navigate-left' ) );
dom.controlsRight = toArray( document.querySelectorAll( '.navigate-right' ) );
@ -440,6 +442,31 @@
dom.controlsPrev = toArray( document.querySelectorAll( '.navigate-prev' ) );
dom.controlsNext = toArray( document.querySelectorAll( '.navigate-next' ) );
dom.statusDiv = createStatusDiv();
}
/**
* Creates a hidden div with role aria-live to announce the
* current slide content. Hide the div off-screen to make it
* available only to Assistive Technologies.
*/
function createStatusDiv() {
var statusDiv = document.getElementById( 'aria-status-div' );
if( !statusDiv ) {
statusDiv = document.createElement( 'div' );
statusDiv.style.position = 'absolute';
statusDiv.style.height = '1px';
statusDiv.style.width = '1px';
statusDiv.style.overflow ='hidden';
statusDiv.style.clip = 'rect( 1px, 1px, 1px, 1px )';
statusDiv.setAttribute( 'id', 'aria-status-div' );
statusDiv.setAttribute( 'aria-live', 'polite' );
statusDiv.setAttribute( 'aria-atomic','true' );
dom.wrapper.appendChild( statusDiv );
}
return statusDiv;
}
/**
@ -1800,6 +1827,7 @@
// stacks
if( previousSlide ) {
previousSlide.classList.remove( 'present' );
previousSlide.setAttribute( 'aria-hidden', 'true' );
// Reset all slides upon navigate to home
// Issue: #285
@ -1823,6 +1851,9 @@
startEmbeddedContent( currentSlide );
}
// Announce the current slide contents, for screen readers
dom.statusDiv.innerHTML = currentSlide.textContent;
updateControls();
updateProgress();
updateBackground();
@ -1888,6 +1919,7 @@
verticalSlide.classList.remove( 'present' );
verticalSlide.classList.remove( 'past' );
verticalSlide.classList.add( 'future' );
verticalSlide.setAttribute( 'aria-hidden', 'true' );
}
} );
@ -1965,6 +1997,7 @@
// http://www.w3.org/html/wg/drafts/html/master/editing.html#the-hidden-attribute
element.setAttribute( 'hidden', '' );
element.setAttribute( 'aria-hidden', 'true' );
// If this element contains vertical slides
if( element.querySelector( 'section' ) ) {
@ -2012,6 +2045,7 @@
// Mark the current slide as present
slides[index].classList.add( 'present' );
slides[index].removeAttribute( 'hidden' );
slides[index].removeAttribute( 'aria-hidden' );
// If this slide has a state associated with it, add it
// onto the current state of the deck
@ -2931,6 +2965,9 @@
element.classList.add( 'visible' );
element.classList.remove( 'current-fragment' );
// Announce the fragments one by one to the Screen Reader
dom.statusDiv.innerHTML = element.textContent.trim();
if( i === index ) {
element.classList.add( 'current-fragment' );
}