Develop Reference

tweenMax 'staggerFrom' and 'From' broken with requestAnimationFrame?

For some reason when I use from or staggerFrom with requestAnimationFrame, the animation jumps and actually acts as if it's doing a "To" tween. When I use the code outside of my requestAnimationFrame, it works fine. Why is this? I need to use within a requestAnimationFrame because I trigger the tween when scroll is at a certain position and I need requestAnimationFrame to determine that position (I was advised that's the correct way to do it instead of attaching to scroll).
Here's my tween:
TweenMax.staggerFrom(".box", 1, { x:100, autoAlpha: .5}, .5);
I made a quick codepen demonstrating this issue.

css animation fast forward and rewind

I was wondering if it was possible, using some javascript or jquery, to skip to the next, or go to the last part of a css animation. Lets say we have the following:
#keyframe effect{
0%{opacity:1;}
45%{opacity:1;}
50%{opacity:0;}
95%{opacity:0;}
100%{opacity:1;}
}
that will fade something out and then back in
so lets say I made some buttons. How would I do the following:
$('#next').click(function(){
//skip to the next animation part
});
$('#previous').click(function(){
//skip to the previous animation part
});

It's not really possible unless you break the CSS into different parts based on classes and then add/remove classes.
However, there is an absolutely fantastic javascript library called Greensock, that allows timeline-based animation - and in many cases is faster than CSS animations. It also has the benefit of being cross-browser compatible.
If you were, for example to create something similar using Greensock, it would look something like this:
var effect = new TimelineMax({paused:true});
effect.addLabel('start');
effect.to(
'#myItem',
1,
{css:{opacity:1}}
);
effect.addLabel('step1');
effect.to(
'#myItem',
1,
{css:{opacity:0}}
);
effect.addLabel('end');
effect.play();
$('#gotoEnd').on('click', function(e){
e.preventDefault();
effect.seek('end');
});

With the use of the animation-play-state Property, you can pause an animation and update the transform, then restart it.
element.style.webkitAnimationPlayState = "paused";
element.style.webkitAnimationPlayState = "running";
However you can't pause the animation, transform it, resume it, and expect it to run fluidly from the new transformed state.
At this time, there is no way to get the exact current "percentage completed" of a CSS keyframe animation. The best method to approximate it is using a setInterval or requestAnimationFrame.
This CSS tricks article explains this further, and gives an example of using setInterval. Another option is to use request animation frame
As mentioned GreenSock or Velocity are animation libraries which allow for extremely fast and smooth animations

Why are style assignments performed immediately after creation not animated?

Opening this fiddle on Webkit will show what I'm talking about.
How can I specify an element's style when it is first specified, and then its final state?
It should be possible to specify a single step animation fully this way (without having to start using #keyframes) but it seems like there is a lot of implementation specific strangeness I must deal with at this point. Note how in Firefox no animation is performed...

Seems to be the same issue as described here: CSS3 transitions to dynamically created elements
so
$("#one").on('click',function(){
var word = $("<div style='opacity: 0; height:0'>word</div>");
$('body').prepend(word);
window.getComputedStyle(word[0]).getPropertyValue("top");
word.css({height: 100, opacity: 1});
});
also works in this case: http://jsfiddle.net/wWnnH/3/

Alternatively, you can use jQuery.animate()
word.animate({height: 100, opacity: 1}, 5000);
Will work without the CSS, and on both webkit and mozilla. Although this defeats the purpose of trying to use CSS3 I guess.

jQuery example (in jsfiddle) working in firefox but not in IE8, 7

Why this example not working in IE http://jsfiddle.net/8RZVt/
I'm getting this error in IE8.
Message: Invalid argument.
Line: 156
Char: 295
Code: 0
URI: http://code.jquery.com/jquery-1.4.4.min.js

According to jQuery, this is because, as stated on the animate documentation page:
All animated properties should be a
single numeric value (except as noted
below); properties that are
non-numeric cannot be animated using
basic jQuery functionality....
So, in fact, in Firefox you are using undefined behavior. The correct thing to do would be to animate on backgroundPositionX, however Firefox does not support this.
There is, however, a jQuery plugin that does what you want:
http://plugins.jquery.com/project/backgroundPosition-Effect
Update
On closer inspection, the plugin does not support += or -= formats.
I hacked it into this example:
http://jsfiddle.net/CxqSs/ (See new example at bottom.)
Could definitely use some cleanup, and should probably be added to that plug-in, but it works in both browsers and doesn't rely on undefined behavior.
BTW, I don't know if it's worth noting, but if you leave this animation running a long time, it will eventually overflow the value and break. This could be overcome by animating the full length of the background image and then resetting the offset to 0px in the callback before the next animate. This would also avoid needing the += format.
Also,
It should be noted that speed: 1, step: 1 and speed: 50, step: 50 are equivalent.
The reason they look different speeds is because
There is more overhead in a speed of 1 (which is really a millisecond duration) because animate gets called more often.
The default easing is "swing", meaning that the animation speeds up and slows down slightly throughout it's course, meaning that the overall speed is affected a bit. You should change the easing to "linear" for your scrolling case:
var animate = function() {
element.animate({
...
}, speed, "linear", animate);
};
This means that you could use the backgroundPosition-Effect plugin, without the '+=', by setting your step to 2247 (the width of the image), like I stated above.
And that finally brings us to... wait for it...
http://jsfiddle.net/zyQj3/20/
Cross-platform, non-kludgy, non-overflowing, correctly easing, extra parameter-lacking, solution.

The script fails at this point because you are passing an invalid CSS value:
element.animate({
backgroundPosition: animStep + " 0px" /* evaluates to "+=50px 0px" */
}, speed, animate);

OK here we go again :D
http://jsfiddle.net/c7rKV/1/
Again identical to original however again just animating backgroundPositionX when in IE.
Apologies on not actually looking at FF/Chrome last time.
Additionally: this of course is not very graceful and Adam Prax is absolutely correct on what the problem is. I just wanted to post a solution to it.

If you check the source code of jQuery, you will see it uses this regexp to parse the parameter (which in your case is +=50px 0px). So it will see it as += (increase) 50 (to fifty) px 0px (unit, append after the number). When trying to read the current value, jQuery uses parseFloat, which just grabs the number at the start of the string. So it works perfectly, even if a multi-dimensional property is probably not what the jQuery programmers had in mind.
Except that IE8 does not support getting the current value of background-position. There is background-position-x and background-position-y but no background-position. Duh. So your best bet is checking the browser type, and animating either background-position or background-position-x depending on that: http://jsfiddle.net/22UWW/
(There is actually a jQuery bug report about this, with a more elegant solution.)

How to force jQuery animations to run simultaneously?

I have a web page with animations (JQuery Animation) all over the place. A typical animation sequence may contain three or four objects animating independently at the same time. The issue I am facing is that the queuing of the animations is not predictable. Some of the animations are running simultaneously while some others are not.
I am doing something like
setTimeout(function(){
//animations
}, delay);
in many places just to try and group the animations. Even when using this, some of the animations inside the code block are not running simultaneously.
Is there any way to force animations to be run at the same time? Is there a way to fill up the queue with animations and then execute these at the same time?
Is there any comprehensive documentation of how this thing actually works?
EDIT: Sample code Warning: The code is messy
The question is looking at the code how do you know which of the animations are going to run simultaneously?

This run simultaneously (but not if there's already an ongoing animation on the object):
$('.blabla .2').animate({opacity: 0.3, fontSize: 20}, 800);
And if you want to be 100% sure that it's animated right away (notice the queue:false):
$('.blabla .1').animate({fontSize: 20},{queue:false,duration:800});
You can also do this. (It will still run simultaneously)
$('.blabla .1')
.animate({fontSize: 20},{queue:false,duration:800})
.animate({opacity: 0.4},{queue:false,duration:800});
This runs one after the other.
$('.blabla .1').animate({opacity: 0.3}, 800).animate({fontSize: 20}, 800);
So does this
$('.blabla .2').animate({opacity: 0.3}, 800, function() {
$('.blabla .3').animate({opacity: 0.3}, 800);
});
I hope that answers your question.
Sorry for all the edits, i'm new here.

Use the step option. You give it a function, and after each step of the current animation, it will execute that function. Thus you can animate there. Link to docs.