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Check scrollTop on touch device

I have the following function that checks the scrolling position of a user so that the menu becomes fixed once they scroll past the masthead
function checkScrolling() {
if( $(window).scrollTop() > $('.masthead').height() ) { // we check against ACTUAL height
$('.menu').addClass('fixed');
}else {
$('.menu').removeClass('fixed');
}
}
and here the desktop and touch screen event listeners:
$(document).bind('touchstart touchend touchcancel touchleave touchmove', function(e){
checkScrolling();
});
$(window).scroll(function(){
checkScrolling();
});
However the touch events only make the menu fixed during the touchmove reliably. If I scroll really fast with a swipe up or down, there is a delay before the menu becomes fixed or unfixed.
Any ideas on how to fix this? See a code example here: http://dev.driz.co.uk/mobileMasthead.html (has been amended based on some answers below, but still does not work correctly on an iPad or iPhone)
Update:
And reading up on the topic reveals that JS like checking scroll position don't happen during the scroll... BUT... I've noticed that http://www.facebook.com/home/ doesn't have this issue when testing it on my iPad. So it's definitely possible to achieve this effect without using any custom JavaScript scrollbars like iScroll or similar.

Maybe I understand the question wrong, but to ensure functionality with high speed scrolling, why don't you tackle it the pure CSS way (aka faking the 'fancy' effect):
Old School (fast but primitive)
HTML
<div id="menu2"></div>
<div class="scroll" id="scroller">
<div id="overlay"></div>
<div id="menu"></div>
</div>
With the simple CSS:
html, body { overflow: hidden; height: 100% }
body { margin:0; padding:0; }
.scroll {
-webkit-overflow-scrolling: touch;
height:960px;
width:640px;
}
#menu2 {
width:640px;
height:20px;
background:red;
position:absolute;
z-index:-1;
}
#menu {
width:100%;
height:20px;
background:red;
z-index:0;
}
You can see a working example HERE.
It may be a bit primitive: but hey! It works! :)
New School (fancy but slow)
Check all of the other answers supplied.
But note that it 'is known' that the usage of JavaScript in combination with scrolling on mobile devices is causing a lot of trouble regarding speed.
That's why I think the simple CSS approach may be better.
If you want to learn about JavaScript and scrolling on mobile devices (and other functions), then there are two articles which I highly recommend reading:
Fast animations with iOS Webkit
Native scrolling: Grins and Gotchas

Facebook doesn't use JavaScript but pure css:
position: -webkit-sticky;
If i remember it correctly this makes the element stick at the top of its parent container when scrolled.

You just needed to attach your scroll events, not to window, document or body, but to a custom container.
On iOS you can't programatically react during these hardware-accelerated window scrolling behaviour.
Here's a fiddle:
a wrapper:
<div id="content">
some not-so-relevant css:
html,body,#content {
width:100%;
height:100%;
}
#content {
background-color: lightblue;
overflow:scroll;
}
attaching the listeners to the container:
function checkScrolling() {
if ($('#content').scrollTop() > mastheadHeight) {
menu.addClass('fixed');
} else {
menu.removeClass('fixed');
}
}
$('#content').scroll(function () {
checkScrolling();
});
You can see it working here for the JS-only fallback:
http://jsfiddle.net/jaibuu/YqPzS/
direct URL: http://fiddle.jshell.net/jaibuu/YqPzS/show/

I once tried to implement sticky headers on mobile version of a site but had encountered whole set of problems.
First and most important is that scroll event does not fire on mobile devices as often as it does on desktop. Usually it does fire when page stops. I don't know the exact reason for that but I can suggest it's because browsers on mobile "send" such tasks to GPU meantime CPU can not keep JS objects up to date with what happens to the canvas (but that's just my suggestion). Newer version of iOSes are making it better for us and probably scroll will work on iPhones.
You should use touch events. This makes you write a separate version of code for devices that support touch input. So have to look for reliable ways of testing for platform.
But touch events are also tricky especially on Android. I thought that in the callback for touchmove event I will be able to figure out current coordinates and go further from that point.
But There this issue https://code.google.com/p/android/issues/detail?id=5491 on Android, in summary touchmove fires once or twice at the very beginning of the touch action and does not fire again. Which makes it totally useless. People are suggesting preventDefault() but you no longer can scroll with that.
So I ended up with idea to reimplement scrolling from scratch using CSS transforms. And here is my results so far:
http://jsbin.com/elaker/23
Open that link on your device and http://jsbin.com/elaker/23/edit on your desktop: you'll be able to edit code and it will live update on you device, very convenient.
NOTE:
I'd like to warn you that this CSS scrolling thing is raw and there are some known problems that are not resolved yet: like you can sometimes scroll beyond top or bottom boundaries or if you just touch (not move) it still will scroll. Also the notorious URL bar will not hide. So there is work to do.

Do you need the touch events to fire this at all? Modern devices should return $(window).scroll() events and scrollTop values. On older Android and and pre-ios5 (I think), position:fixed: didn't work as expected because the of how the viewport worked. But it has been corrected in all new releases.
To further debug devices, I highly recommend Adobe Edge Inspect. You could console.log the scrollTop and see if the devices you care about actually work correctly with out any trickery. You'll get everything you need with their free version.

A great way to dealing with scroll events is not to attach your checks to the scroll event
takes a lot of resources and doesn't work very well with older browsers.
fortunately you can have a lot more control if you just perform a time loop to do that.
codewise that looks like that:
(It's used by twitter)
var MyMenu = $('#menu'),
didScroll = false;
$(window).scroll(function() {
didScroll = true;
});
setInterval(function() {
if ( didScroll ) {
didScroll = false;
//Do your check here
checkScrolling();
}
}, 180);
You should put your $('.masthead').height() outside this checkScrolling function of yours (in a higher scope) as this kind of operations takes a lot of resources and always ask jquery to "select your element" and calculate its size will eventually make your application laggy:
var headerHeight = $('.masthead').height()
function checkScrolling()
.....
Last thing , you can change the value of the interval attribute (right now it's 180 (a bit more that 60hz -. refresh time of the screen) you can make this value bigger, if you want your app to be more performant but a bit less accurate)
Thanks John Resig and twitter:
http://ejohn.org/blog/learning-from-twitter/
Hope that helped
Ajios !

I have just tested your functions for efficiency. You should try this
function checkScrolling() {
if( $(window).scrollTop() > mastheadHeight )menu.css('position','fixed');
else menu.css('position','');
}
This will reduce function call of addClass and RemoveClass and your execution time will take effect. If you want to reduce more execution time, then better to use pure JavaScript

$(document).ready(function(){
var p = $("#stop").offset().top;
$(window).scroll(function(){
if(p<$(window).scrollTop()){
console.log("div reached");
$("#stop").css({position:"fixed",top:0});
}
else{
console.log("div out");
$("#stop").css({position:"static"});
}
})
});
I think this will help you.
The total code is here in jsfiddle.net.
I have tested it for ipad using safari of online ipad2 simulator in http://alexw.me/ipad2/ and it has worked there. So, I think it will work on real ipad too.

setScrollTop: function(inTop) {
var top = Math.max(0,inTop);
if (wm.isMobile) { // should always be true for touch events
top = Math.min(top, this.listNode.clientHeight - this.listNodeWrapper.clientHeight);
if (dojo.isWebKit) {
this.listNode.style.WebkitTransform = "translate(0,-" + top + "px)";
} else if (dojo.isMoz) {
this.listNode.style.MozTransform = "translate(0,-" + top + "px)";
} else if (dojo.isOpera) {
this.listNode.style.OTransform = "translate(0,-" + top + "px)";
} else if (dojo.isIE) {
this.listNode.style.MsTransform = "translate(0,-" + top + "px)";
}
this.listNode.style.transform = "translate(0,-" + top + "px)";
this._scrollTop = top;
this._onScroll();
} else {
this.listNode.scrollTop = top + "px";
}
},

Force Android browser to redraw every second

I'm moving a very long image using -webkit-transform: translate(-958px, 0); animation
The image gets cut off very soon after it starts to move horizontally, but if I slightly move the tablet screen, it redraws the screen and it displays the whole image while panning across and very smoothly too.
But how do I simulate this in code?

Some suggestion:
Provide the tablet model and android version may help
Information like image dimension and size, animation duration, or a demo page on jsfiddle/jsbin will help a lot
Back to the question:
in the performance term, using translate3d will get better performance, since it doesn't work, the main bottleneck is elsewhere.
from my experience with mobile webkit, when there is large image (in term of size or dimension), you may have trouble:
Ram problem
High Network Delay
Long enough loading and rendering time
If your UI-triggered redraw will smooth everything, the lag may be caused by image loading & rendering
Solution:
Set a reasonable delay on your animation by animation-delay or setTimeout
More precise: preload the image, and then trigger the animation when it is done by listening its onload event: jQuery .load explanation on image load event behaviour
If the above not work for you, try it: Force-redraw DOM technique for WebKit-based browsers
For 2 & 3, the code will be like this:
$("<img>")
.attr({ src: " /* image url */ " })
.load(function(){
/* i. use class or animationName to set animation */
/* ii. force redraw go there if needed */
/* wrap i & ii into a setTimeout function inside this callback
if more delay is needed */
})
good luck.

This little snippet of code and blog post from Paul Irish might be helpful to you:
http://paulirish.com/2011/requestanimationframe-for-smart-animating/
And it's nearly cross browser if that floats your boat.

Forgive me if I'm not reading your question right.
Are you planning on using the tablet's gyro to pan about a large image? That should be possible in code.
However, forcing a transition to update faster is out of the developer's control, to my knowledge. The best you can do is make sure that that is all the tablet has to worry about.
<!DOCTYPE html>
<html>
<head>
<style>
body {
padding:0px;
overflow:hidden;
}
#img {
position:absolute;
left:0px;
top:20px;
-webkit-transition:left 0.5s;
}
</style>
</head>
<body>
<img id="img" src="img.png" />
</body>
<script>
function onOrientationChange(e) {
var img = document.getElementById("img");
var maxWidth = img.clientWidth - document.body.clientWidth;
img.style.left = ((e.gamma-90) * maxWidth / 180 ) + "px";
}
window.addEventListener('deviceorientation', function(e){onOrientationChange(e)}, true);
</script>
</html>

Have you tried using translate 3d? GPU kicks in when it's used.
HTML5 App/Animation Performance

jquery javascript resize jitter

I have some simple javascript that I'm using to auto-adjust the width of elements on pages and to vertically center the text on these pages.
My script works, but in IE9 and a little in Safari there is a distinct moment where the elements are not resized and they jump across the page. It's just a momentary flash, but it bugs me as I'm generally not a "good enough" kind of person. Here is my own script:
$(document).ready(function() {
var containerwidth = $("#main_content").css("width");
var picwidth = $(".picture").css("width");
$(".picture").parent().css("width", picwidth);
var correctwidth = parseInt(containerwidth) - parseInt(picwidth);
$(".main-text").css("width",correctwidth-25);
if( $(".margins").css("width") ) {
$(".title").css("width", parseInt($(".width-set").css("width"))+10);
} else {
$(".title").css("width", parseInt($(".title").parent().css("width"))-10);
}
var container_height = $(".main-text").height();
var text_height = $(".vert-align").height();
var offset = (container_height - text_height) / 2;
$(".vert-align").css("margin-top", offset);
[...]
});
I realize the use of explicit offsets and whatnot is hackish, but I'm in a hurry and will correct it later. And yes, I am using jQuery.
This is stored in a file, and I've tried both calling it in the head, and also directly after the elements it affects, but the result is the same. Is this jitter just a fact of life for using element manipulation with javascript, or is there some solution I've missed on the forums?
Thanks!

I suspect the reason is because you are calling this in the $(document).ready(), which runs after the DOM is loaded (i.e. your elements are already displayed).
If you absolutely have to resize elements after they've loaded, the only thing I can think of that might help is having an overlay that covers the entire window, maybe something like:
#overlay{
position: fixed;
width: 100%; height: 100%;
background: #fff;
z-index: 9001;
}
And then hiding the overlay via $("#overlay").hide() after the resizing in your $(document).ready() function. I haven't tested this so I don't know if it works. You might have to add a short setTimeOut as well.
To be honest, though, this solution feels very dirty. Hopefully someone else can think of something more elegant.

#ZDYN is correct. The "flicker" happens when the page is displayed but the jQuery code has not been executed.
You can try to set in the css your elements to "visibility: hidden" so they will have their dimensions for the calculations, then change the visibility to "visible" after the resizing.

Continuously scrolling horizontal ticker containing images in jQuery?

I would like to do something like this: http://javascript.about.com/library/blcmarquee1.htm
The script I referenced however seems to be a bit laggy (outdated?), so I was wondering if anyone knew of a better solution. (jQuery solutions welcome.)

Just found this — jQuery-driven, and has images. I’m intending to use it for a current project.
http://logicbox.net/jquery/simplyscroll/
UPDATE: I have now used this in production code. The plugin is capable of looping 70+ 150×65px images pretty smoothly - which a number of another plugin I tried similar to this were failing on.
NOTE it reeked havoc with z-index issues in IE 6 / 7 and was not showing up etc. - But this might also have been partly due to my CSS. To anyone having trouble with it not showing up at all in IE check out the standard IE z-index fixes: http://www.google.com/search?q=ie+z+index+issues
LATEST UPDATE:
Addition things to consider when implementing plug-ins like these:
The number of items and type of content to scroll. I found a number that would start to glitch as soon as you had more than say 15 images to scroll.
I found a number of these plugins that were tied to old versions of jquery
If scrolling images ARE THEY ALL THE SAME SIZE again a number of the plug-ins I experimented with only worked if all the images were the same size but did not make this clear in the tutorials. I believe then the plugins run then set a string of li tags that are all x wide then calculate the total distance of them all chained together to manage the scrolling.
Effects - some would continuously scroll others would move one image pause for a second then move another image
I have now also found these two scroller plugins to be very good as well.
http://caroufredsel.frebsite.nl/
http://sorgalla.com/jcarousel/

The Silky-Smooth jQuery Marquee and Giva Labs' Marquee

Just a thought. Could you do something like this.
<style type="text/css">
.imgwindow{
width:500px; //or whatever
height:65px; //or whatever
position:relative;
overflow:hidden;
}
.imgholder{
min-width:2000px;
height:65px;
position:absolute;
left:-200px;
}
.inline-image{
display:inline-block;
}
</style>
<script type="text/javascript">
var img;
function imgScroll(){
img = $(".inline-image").first();
img.animate({width:0},2500,'linear',function(){
img.remove();
$(".imgholder").append(img);
imgScroll();
});
}
$(document).ready(function(){
imgScroll();
});
</script>
and the html
<div class="imgwindow">
<div class="imgholder">
<img class="inline-image" src="image1" /><img class="inline-image" src="image2" />...
</div>
</div>

Rotating Div using javascript

Here is a link: http://www.avineon.com/
Open this link see on the top. Four images are rotating.
I need something similiar using Javascript.
Is it possible by using Javascript.

I don't think you'll have much luck if you try to do that in pure javascript. It might be possible using the emerging canvas and SVG libraries such as Raphael, but you'll still have cross-browser issues. That site used Flash, and I'd recommend using that if you wanted such an effect.
...why you'd want that on your website is another story though...

You could so something similar, but not exact.
Transparency = Supported in FF, Safari, IE7+
Changing image width = Place image in div with this Css
.class img {
display: block;
width: 100%;
height: 100%
}
This will make the image stretch to fill the .class div. You can then use JS to make this div narrower like the carousel does, and the image contained will animate within the div.
You would then need to track the mouse locations to determine how fast it spins.
You can use an equation using cosine for smooth acceleration from the far ends (IIRC)
You will not however be able to get the images in reverse, unless you create a copy in a server side language or use canvas.

Your best bet would not be to attempt to render something in actual 3D, but rather to use visual tricks to approximate a 3D effect. That is, use perspective / image deformation to make it look like a cube is rotating, similar to what is implemented at this page, which has a better explanation of the math involved.
Really, though, you're probably better off just using Flash.

That effect is possible in JavaScript simply by modifying each of the images width, height, and left styles over time. It's an involved script, but only needs to interpolate those three styles on the each of the image elements.
To get the rotation effect, decrement the width style of the image in a setInterval function while moving the left style property. There is a slight decrement on the height also.
You'll need two images for each side, a front and reverse. When the width decrements to zero, swap the image with it's flipped version and start incrementing the width.
Alternatively use Webkit's, and Firefox's transform css properties.
Or try one of these coverflow components that look similar:
Protoflow,
ImageFlow

<html>
<head>
<title></title>
</head>
<body>
<script type="text/javascript">
if (document.all || document.getElementById){ //if IE4 or NS6+
document.write('<style type="text/css">\n');
document.write('.dyncontent{display: none; width: 728px; height: 90px;}\n');
document.write('</style>');
}
var curcontentindex=0;
var messages=new Array();
function getElementByClass(classname){
var inc=0;
var alltags=document.all? document.all : document.getElementsByTagName("*");
for (i=0; i<alltags.length; i++){
if (alltags[i].className==classname)
messages[inc++]=alltags[i];
}
}
function rotatecontent(){
//get current message index (to show it):
curcontentindex=(curcontentindex<messages.length-1)? curcontentindex+1 : 0;
//get previous message index (to hide it):
prevcontentindex=(curcontentindex==0)? messages.length-1 : curcontentindex-1;
messages[prevcontentindex].style.display="none"; //hide previous message
messages[curcontentindex].style.display="block"; //show current message
}
window.onload=function(){
if (document.all || document.getElementById){
getElementByClass("dyncontent");
setInterval("rotatecontent()", 5000);
}
}
</script>
<table width="100%">
<tr align="center">
<td>
<div class="dyncontent" style="display: block">
first
</div>
<div class="dyncontent">
second
</div>
<div class="dyncontent">
Third
</div>
</td>
</tr>
</table>
</body>
</html>