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generalize scroll offset prevention

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This commit is contained in:
Hakim El Hattab 2016-04-07 09:07:19 +02:00
parent 00b9c2b929
commit 520fa4986e
1 changed files with 15 additions and 15 deletions
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30
js/reveal.js
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@ -410,8 +410,8 @@
// Listen to messages posted to this window
setupPostMessage();
// Prevent iframes from scrolling the slides out of view
setupIframeScrollPrevention();
// Prevent the slides from being scrolled out of view
setupScrollPrevention();
// Resets all vertical slides so that only the first is visible
resetVerticalSlides();
@ -642,22 +642,22 @@
}
/**
* This is an unfortunate necessity. Iframes can trigger the
* parent window to scroll, for example by focusing an input.
* This is an unfortunate necessity. Some actions – such as
* an input field being focused in an iframe or using the
* keyboard to expand text selection beyond the bounds of
* a slide – can trigger our content to be pushed out of view.
* This scrolling can not be prevented by hiding overflow in
* CSS so we have to resort to repeatedly checking if the
* browser has decided to offset our slides :(
* CSS (we already do) so we have to resort to repeatedly
* checking if the slides have been offset :(
*/
function setupIframeScrollPrevention() {
function setupScrollPrevention() {
if( dom.slides.querySelector( 'iframe' ) ) {
setInterval( function() {
if( dom.wrapper.scrollTop !== 0 || dom.wrapper.scrollLeft !== 0 ) {
dom.wrapper.scrollTop = 0;
dom.wrapper.scrollLeft = 0;
}
}, 500 );
}
setInterval( function() {
if( dom.wrapper.scrollTop !== 0 || dom.wrapper.scrollLeft !== 0 ) {
dom.wrapper.scrollTop = 0;
dom.wrapper.scrollLeft = 0;
}
}, 1000 );
}