Firefox is exhibiting this behavior (bug?) that occurs after exiting a full screened <img> where the user ends up at the element that sits above the <img> the user had just viewed in fullscreen. In short my question is:
How can I prevent Firefox from scrolling up after exiting fullscreen mode?
The MCVE posted as a Snippet doesn't function due to SO's strict security measures so I have provided a plunker. All the details are commented in the Snippet and Plunker. In addition I have added a simple interface to not only reproduce the issue but to change the layout to test different combinations as well. Thank you for your valuable time.
SNIPPET (doesn't function--review this plunker instead)
/* Several attempts to use the .focus() method
|| and focus events did not work for me, neither
|| has tabindex and anchors. If it appears that
|| my implementation is wrong (a strong possibility)
|| please inform me.
*/
$('a').click(function(e) {
var tgt = $(this).prev();
fs(tgt[0]);
$(this).focus();
});
/* This function is for the MCVE
|| It enables the ~select~ to remove and re-insert
|| the test elements. By doing so, we can see
|| how the test elements behave in different
|| combinations. What I found out about FF is
|| that when exiting a full screened ~img~ that's
|| positioned last is that it will lose focus
|| and the viewport is scrolled up to the element
|| above it.
*/
$('#sel1').on('change', function(e) {
var V = $(this).val();
var first = $('#' + V).find(':first').attr('id');
if ($('#' + V).hasClass('media')) {
$('#' + V).fadeOut('#' + first);
} else {
$('#' + V).fadeIn('#' + first);
}
$('#' + V).toggleClass('media');
});
/* These 2 functions are responsible for
|| full screen. Please inform me if there's a
|| better way, or if anything is outdated. I
|| have researched the Fullscreen API and I
|| haven't found any updates of any use. I've
|| used these functions for the last 3 years
|| so maybe I might've missed something
|| critical.
*/ // There's no ms prefixes because I'm not concerned about IE.
var isFullScreen = function() {
return !!(document.fullscreenElement || document.webkitFullscreenElement || document.mozFullScreenElement);
}
function fs(target) {
if (!isFullScreen()) {
if (target.requestFullscreen) {
target.requestFullscreen();
} else if (target.webkitRequestFullscreen) {
target.webkitRequestFullscreen();
} else if (target.mozRequestFullScreen) {
target.mozRequestFullScreen();
}
} else {
if (document.exitFullscreen) {
document.exitFullscreen();
} else if (document.webkitExitFullscreen) {
document.webkitExitFullscreen();
} else if (document.mozCancelFullScreen) {
document.mozCancelFullScreen();
}
}
}/* These styles are here for the demo itself
|| and are not a cause of the problem at hand
*/
* {
margin: 0;
padding: 0
}
body {
font: 400 16px/1.3 Consolas;
height: 100%;
width: 100%;
background: #333;
color: #fed
}
a {
margin: 0 auto 50px;
display: block;
width: 48px;
height: 48px;
text-align: center;
cursor: pointer;
background-size: contain;
}
.vid,
.img,
.gif,
.svg {
display: block;
margin: 20px auto;
}
.expand {
background: url(http://imgh.us/expand_2.svg)no-repeat;
}
header {
padding: 15px 10px;
margin: 15px auto;
}
fieldset {
border: 10px solid tomato;
width: 20ch
}
legend {
font-size: 1.2em;
}
dt {
text-decoration: underline;
font: 1.1em;
}
dd {
margin-left: 20px
}
.note,
dt {
color: #ffcc33
}
.demo {
width: 450px;
padding: 10px;
counter-reset: step;
}
.demo li::before {
counter-increment: step;
content: "» " counter(step) ". ";
text-indent: -150px;
margin-left: 30px;
color: cyan;
}
.fs:-webkit-full-screen {
max-width: 100%;
height: auto;
}<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1, user-scalable=no">
<title>Prevent Firefox from Moving After .exitFullscreen()</title>
<style>
</style>
</head>
<body>
<header>
<dl>
<dt>Objective</dt>
<dd>Prevent Firefox from Moving After .exitFullscreen()</dd>
<dt>Behavior</dt>
<dd><b class='note'>Expected: </b>When exiting fullscreen mode, we should be at the same position that we were at before</dd>
<dd><b class='note'>Experienced: </b>In FF, when exiting fullscreen mode, we are scrolled up as if the element above has a higher tab priority or more than likely is that tab index and focus are being ignored by FF.</dd>
<dt>Question</dt>
<dd><b><mark>How can I prevent Firefox from scrolling up after exiting fullscreen mode?</mark></b></dd>
</dl>
</header>
<section>
<ol class='demo'>
<li>To reproduce issue, use the <select> to remove items C, D, E, and F.</li>
<li>Next, fullscreen item B by clicking the icon below it.</li>
<li>Then exit full screen mode by hitting <kbd>ESC</kbd>.</li>
<li>Notice we have jumped up the page.</li>
</ol>
</section>
<!--This ~select~ is for the MCVE - details are
commented below in the ~script~ block-->
<section>
<fieldset>
<legend>Remove and Re-insert Elements</legend>
<select id='sel1'>
<option value="">----</option>
<option value='A'><video> src=MP4</option>
<option value='B'><img> src=PNG</option>
<option value='C'><video> poster=GIF</option>
<option value='D'><img> src=SVG</option>
<option value='E'><div> &nbsp;</option>
<option value='F'><iframe> srcdoc="<DIV><div>"</option>
</select>
</fieldset>
<!--I tried using the ~a~nchors, -id-, -name-, and -tabindex-
FF was ignoring my attempts to keep or get focus. Using named or
id ~a~nchors failed since the distance between desired spot
and the spot FF ends up at is short.-->
<div id='A' class='media'>
<video id="vid1" class="vid fs" src="http://html5demos.com/assets/dizzy.mp4" controls></video>
<a href='#/' class='expand' tab-index='1'></a>
</div>
<div id='B' class='media'>
<img id='img1' class='img fs' src='http://imgh.us/Lenna.png'>
<a href='#/' class='expand' tab-index='1'></a>
</div>
<div id='C' class='media'>
<video id='gif1' class='gif fs' poster='http://imgh.us/gir_zim.gif' width='300' height='300'></video>
<a href='#/' class='expand' tab-index='1'></a>
</div>
<div id='D' class='media'>
<img id='svg1' class='svg fs' src='http://www.clker.com/cliparts/j/g/8/S/V/O/test.svg' width='auto' height='500'>
<a href='#/' class='expand' tab-index='1'></a>
</div>
<!--Subjects E and F were added to see if a "dummy"
element were to be the last element so that FF
would exit fullscreen on the last ~img~ correctly.
I got mixed results.-->
<div id='E' class='media'>
<div id='div1' class='fs'> </div>
<a href='#/' class='expand' tab-index='1' height='1' width='1'></a>
</div>
<div id='F' class='media'>
<iframe id='ifm1' class='fs' srcdoc="<div style='color:lime'>iframe srcdoc</div><div style='color:cyan'>2 divs</div>" allowfullscreen></iframe>
<a href='#/' class='expand' tab-index='1' height='1' width='1'></a>
</div>
<footer class='bottom'> </footer>
</section>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.2/jquery.min.js"></script>
<script>
</script>
</body>
</html>This answer is fully credited to @Kaido and I'll readily replace this answer if and when Kaido posts an answer.
My attempts at using the scroll methods didn't work is because I was listening to click events when I should've been listening for the onmozfullscreenchange
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Prevent Firefox from Moving After .exitFullscreen()</title>
<style>
button {
display: block;
padding: 0;
width: 32px;
height: 32px;
text-align: center;
cursor: pointer;
background-size: contain;
}
.expand {
background: url(http://imgh.us/expand_2.svg)no-repeat;
}
</style>
</head>
<body>
<div id='A' class='media'>A
<video id="vid1" class="vid fs" src="http://html5demos.com/assets/dizzy.mp4" controls></video>
</div>
<div id='B' class='media'>B
<img id='img1' class='img fs' src='http://imgh.us/Lenna.png'>
<button class='expand'></button>
</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.2/jquery.min.js"></script>
<script>
$('button').click(function(e) {
e.preventDefault();
var tgt = $(this).prev();
fs(tgt[0]);
});
/* This function is for the MCVE
|| It enables the ~select~ to remove and re-insert
|| the test elements. By doing so, we can see
|| how the test elements behave in different
|| combinations. What I found out about FF is
|| that when exiting a full screened ~img~ that's
|| positioned last is that it will lose focus
|| and the viewport is scrolled up to the element
|| above it.
*/
$('#sel1').on('change', function(e) {
var V = $(this).val();
var first = $('#' + V).find(':first').attr('id');
if ($('#' + V).hasClass('media')) {
$('#' + V).fadeOut('#' + first);
} else {
$('#' + V).fadeIn('#' + first);
}
$('#' + V).toggleClass('media');
});
/* These 2 functions are responsible for
|| full screen.
*/ // There's no ms prefixes because I'm not concerned about IE.
var isFullScreen = function() {
return !!(document.fullscreenElement || document.webkitFullscreenElement || document.mozFullScreenElement);
}
// SOLUTION XXXXXXXXXX]START[XXXXXXXXXXXXXXX
var yOffset;
document.onmozfullscreenchange = function() {
if (!isFullScreen()) {
window.scrollTo(0, yOffset);
}
};
// SOLUTION XXXXXXXXXXX]END[XXXXXXXXXXXXXXXX
function fs(target) {
if (!isFullScreen()) {
yOffset = pageYOffset;
if (target.requestFullscreen) {
target.requestFullscreen();
} else if (target.webkitRequestFullscreen) {
target.webkitRequestFullscreen();
} else if (target.mozRequestFullScreen) {
target.mozRequestFullScreen();
}
} else {
if (document.exitFullscreen) {
document.exitFullscreen();
} else if (document.webkitExitFullscreen) {
document.webkitExitFullscreen();
} else if (document.mozCancelFullScreen) {
document.mozCancelFullScreen();
}
}
}
</script>
</body>
</html>