jQuery Forum

velocity.js is a high-performance Javascript animation library. Optionally, it can retrofit jQuery animation functions so that they all use the high-performance code. This is great for updating older code that uses jQuery animation functions.

But jQuery Mobile doesn't use jQuery's animation functions for page transitions. It uses CSS3 animation.

The animation functions in jQuery were written at a time when CSS3 animation did not yet exist. At the time, there was no other way to do animation than to use Javascript code. But the jQuery animation functions  are old and they are slow. For most uses, it is better to use CSS3. And jQuery Mobile already does. When jQuery Mobile was created, CSS3 animation was now in wide use, and the decision was made to use it. It doesn't use those old, slow, Javascript animation functions, and so velocity cannot help.

If you post your specific problem, show us a demo, mention what version of jQuery Mobile, etc. perhaps we can help. Usually, though, the problem is unrealistic expectations on older hardware. Older Android devices have particularly bad CSS animation performance. Certain fancy transitions such as "flip" are particularly bad. I find that for older Android, it's better to stick to something simple - like "fade"...

Thank you for the quick response, I set now. I use a Sony Xperia E1 android 4.4.2, I find that performance is not optimal. After I grant you, it is not the high-end smartphone, but it still scares me to know that on older than mine smartphone, transitions are low even using slide or fade (problem flashing).

News on the performance of JQM 1.5 coming?

I do not like the "sequential" transitions since JQM 1.1 and on, and so I wrote a little "plug in" (not really a formal plugin) so that you can use the "simultaneous" transitions from JQM 1.0. Ironically, this is the one thing that 1.0 did well. (But only practical if you page does not scroll, which is why the transitions were changed.)

But there are caveats:

- I never updated it for 1.4.x. Not sure if it even works on 1.3. Probably not.

- It works only if the page does not scroll. That is not a problem for me, because I always use iScroll between a fixed header and footer, so there are no issues with page height.

It's here:

    https://github.com/watusi/jquery.mobile.simultaneous-transitions

I'm not sure that I will update this, since the JQM transitions have improved. If you want to contribute an update, I'd be glad to answer some questions. Feel free to post an Issue or Issues on GitHub and I will respond.

I am re-writing jquery.mobile.iscrollview and the new one will work with iScroll5 and with jQuery, jQuery UI, or jQuery Mobile (it will be called jquery.iscroll). When I am done with that, I will look at bringing Simultaneous Transitions up to date.

Thank you, you're right CSS transitions can only advanced hardware.

However, according to the roadmap, they plan to work on navigation in general and not specifically on the transitions.

A small glimmer of hope in demo jquery mobile 1.4.5

Important:  Some platforms currently have issues with transitions. We are working on a solution to solve the problem for everyone. If you are experiencing flickers and flashes during or at the end of a transition we suggest the following workaround. Please note that this workaround should be thoroughly tested on the target platform before deployment. This workaround is known to cause performance issues and browser crashes on some platforms, especially Android. 

Then I would have to use your plugin and try to update it but all pages scrolls.

Finally I think maybe create your own transitions, I do not know if it can be more efficient, is that such an approach has already been demonstrated? JQM bases transitions they will conflict generated ?

Using  $.mobile.transitionHandlers