Getting a sticky header to "push up", like in Instagram's iPhone app using CSS and jQuery
There's not a quick or easy answer to this but with a bit of creative cajoling we can emulate the same functionality.
What we need is a series of elements we can identify, loop over and then set up so that when we hit their position on the page the previous item is pushed up and the new item becomes fixed. We will need to retrieve the element's initial position using jQuery's offset().top method and store it in a data tag so we can reference it later. Then the rest will be calculated as we scroll.
This should do the trick:
var stickyHeaders = (function() {
var $window = $(window),
$stickies;
var load = function(stickies) {
if (typeof stickies === "object" && stickies instanceof jQuery && stickies.length > 0) {
$stickies = stickies.each(function() {
var $thisSticky = $(this).wrap('<div class="followWrap" />');
$thisSticky
.data('originalPosition', $thisSticky.offset().top)
.data('originalHeight', $thisSticky.outerHeight())
.parent()
.height($thisSticky.outerHeight());
});
$window.off("scroll.stickies").on("scroll.stickies", function() {
_whenScrolling();
});
}
};
var _whenScrolling = function() {
$stickies.each(function(i) {
var $thisSticky = $(this),
$stickyPosition = $thisSticky.data('originalPosition');
if ($stickyPosition <= $window.scrollTop()) {
var $nextSticky = $stickies.eq(i + 1),
$nextStickyPosition = $nextSticky.data('originalPosition') - $thisSticky.data('originalHeight');
$thisSticky.addClass("fixed");
if ($nextSticky.length > 0 && $thisSticky.offset().top >= $nextStickyPosition) {
$thisSticky.addClass("absolute").css("top", $nextStickyPosition);
}
} else {
var $prevSticky = $stickies.eq(i - 1);
$thisSticky.removeClass("fixed");
if ($prevSticky.length > 0 && $window.scrollTop() <= $thisSticky.data('originalPosition') - $thisSticky.data('originalHeight')) {
$prevSticky.removeClass("absolute").removeAttr("style");
}
}
});
};
return {
load: load
};
})();
$(function() {
stickyHeaders.load($(".followMeBar"));
});.followMeBar {
background: #999;
padding: 10px 20px;
position: relative;
z-index: 1;
color: #fff;
}
.followMeBar.fixed {
position: fixed;
top: 0;
width: 100%;
box-sizing: border-box;
z-index: 0;
}
.followMeBar.fixed.absolute {
position: absolute;
}
/* For aesthetics only */
body {
margin: 0;
font-family: Segoe, "Segoe UI", "DejaVu Sans", "Trebuchet MS", Verdana, sans-serif;
}<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="followMeBar">A</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">B</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">C</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">D</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">E</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">F</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">G</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">H</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">I</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">J</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">K</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">L</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">M</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">N</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">O</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">P</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">Q</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">R</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">S</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">T</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">U</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">V</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">W</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">X</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">Y</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<div class="followMeBar">Z</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>Here's the CSS only version:
Before you say "What?! I just went through all of that when there's a CSS only version?!" It only works in a couple of browsers. Try this in firefox for example:
.sticky {
position: -webkit-sticky;
position: -moz-sticky;
position: -o-sticky;
position: -ms-sticky;
position: sticky;
top: 0;
left: 0;
right: 0;
display: block;
z-index: 1;
background: #999;
color: #fff;
padding: 10px 20px;
}
/* For aesthetics only */
body {
margin: 0;
font-family: Segoe, "Segoe UI", "DejaVu Sans", "Trebuchet MS", Verdana, sans-serif;
}<div data-lorem="p">
<span class="sticky">a</span>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</div>
<div data-lorem="p">
<span class="sticky">b</span>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</div>
<div data-lorem="p">
<span class="sticky">c</span>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</div>
<div data-lorem="p">
<span class="sticky">d</span>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</div>
<div data-lorem="p">
<span class="sticky">e</span>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</div>
<div data-lorem="p">
<span class="sticky">f</span>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</div>
<div data-lorem="p">
<span class="sticky">g</span>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</div>
<div data-lorem="p">
<span class="sticky">h</span>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</div>http://caniuse.com/#feat=css-sticky
First off, thanks to @Chris Spittles for his excellent answer.
I've created a modified version that removes the need to wrap each sticky element, as it simply changes their relative position instead of using fixed positioning.
var stickyHeaders = (function() {
var $stickies;
var load = function(stickies, target) {
if (typeof stickies === "object" && stickies instanceof jQuery && stickies.length > 0) {
$stickies = stickies.each(function() {
var $thisSticky = $(this);
$thisSticky
.data('originalPosition', $thisSticky.offset().top)
.data('originalHeight', $thisSticky.outerHeight());
});
target.off("scroll.stickies").on("scroll.stickies", function(event) {
_whenScrolling(event);
});
}
};
var _whenScrolling = function(event) {
var $scrollTop = $(event.currentTarget).scrollTop();
$stickies.each(function(i) {
var $thisSticky = $(this),
$stickyPosition = $thisSticky.data('originalPosition'),
$newPosition,
$nextSticky;
if ($stickyPosition <= $scrollTop) {
$newPosition = Math.max(0, $scrollTop - $stickyPosition);
$nextSticky = $stickies.eq(i + 1);
if($nextSticky.length > 0) {
$newPosition = Math.min($newPosition, ($nextSticky.data('originalPosition') - $stickyPosition) - $thisSticky.data('originalHeight'));
}
} else {
$newPosition = 0;
}
$thisSticky.css('transform', 'translateY(' + $newPosition + 'px)');
//could just as easily use top instead of transform
//$thisSticky.css('top', $newPosition + 'px');
});
};
return {
load: load
};
})();
$(function() {
stickyHeaders.load($(".followMeBar"), $(window));
});
The css is simplified to:
.followMeBar {
background: #999;
padding: 10px 20px;
position: relative;
z-index: 1;
color: #fff;
}
/* For aesthetics only */
body {
margin: 0;
font-family: Segoe, "Segoe UI", "DejaVu Sans", "Trebuchet MS", Verdana, sans-serif;
}
http://plnkr.co/edit/wk3h40LfBdN1UFtDLZgY?p=preview
And here's another example showing how you can have an offset when using a fixed header:
http://plnkr.co/edit/8YBqdCIKruVKYRXbZnCp?p=preview
I tried solutions provided above but none of them working perfectly without bug (mostly bug on scrolling and browser compatibility). Just found this one https://github.com/sarahdayan/feedify and it's working good for me.