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Comment by viscanti | Hacker News Reader

It's nice to see that they're putting effort into this, but the "True Fixed Toolbars" are still broken. That's been the biggest reason I've avoided the project so far. They're using css fixed positioning which is now better supported on mobile devices, but it produces an "uncanny valley" effect now. The "fixed" toolbars move up and down slightly as the page scrolls. That gives you 99% of the effect you're going for, but that 1% just makes it feel awkward and out-of-place.

The Sencha touch team had this sorted out over a year ago. There's really no excuse to not have this feature, or to have a broken implementation. Hopefully the jQuery Mobile team gets it sorted out eventually.

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Hi, I work on the project full time so maybe I can address this directly.

Sencha uses a javascript scroller to provide the fixed headers and footers. There are two very important reasons the jQuery Mobile project is avoiding this implementation:

1. It doesn't feel native. Sencha has done an enormous amount of work to make sure that the scrolling is efficient and they deserve a lot of credit for their hard work but the physics are different for every platform. 2. To implement scrolling regions on Android you have to `return false` on `touchstart` which breaks the use of form elements in the scrolling region. We, as a project, all agree that's not acceptable.

Sencha and jQuery Mobile seem to be solving two very different problems. jQM delivers something that works across a variety of browsers that Sencha is not capable of serving to. Doing this will limit some of the solutions that can be put into place, for certain.

How does Sencha Touch compare to jQuery Mobile, in general? They are both open source, which is desirable, but I'm not sure which one will mature the most in the next year or so.

I decided against Sencha Touch because it doesn't use HTML- you construct the entire site using their JS functions. So if you ever want to transition away from Sencha, you can't- you're locked in.

While I'm not that happy with jQuery Mobile, it does use HTML for layouts. So you can abandon the library without losing all your work. Indeed, I'm starting that process myself right now- custom building something more suitable to my needs, and copy and pasting HTML to bring my existing UI work along with me.

With all due respect, I don't think this is a strong enough reason against Sencha.

Just because jQuery Mobile lets you use HTML, it doesn't mean that it's easy to swap it with some other library. I think jQuery Mobile will dictate how your HTML looks like to a certain degree. If you ever decide to change the library, I think you will have to re-do the whole UI anyway just like Sencha.

I am not saying that there can not be other reasons to not use Sencha, but in my opinion, this one is not.

I think jQuery Mobile will dictate how your HTML looks like to a certain degree.

Oh, absolutely. But it uses standard elements a lot- so a textbox is an <input>, a dropdown is a <select>, and so on. It depends how much you depend on their UI defaults, but in my case I've found it a very simple process to bring the UI over. It needs some CSS tweaks to look pretty again, but the rest "just works".

I quickly build a mobile web app using jQuery Mobile and re-used a lot of code and functionality from our desktop web app. I had to disable some jQuery Mobile functionality but I had something working in less than a week. This wouldn't have been possible if jQuery mobile isn't just a wrapper over HTML and JavaScript.

Sencha Touch feels a lot further along in development. They've been "feature complete" for a while, and most of their focus is on performance.

I think the tradeoff is in the learning curve. jQuery Mobile is probably easier for most developers to pick up and get going right away. Sencha Touch could take a bit more work for you to get up to speed with (but they're doing a better job of documenting their API).

To answer your question: I think within a year jQuery Mobile will be lucky to get to where Sencha Touch is now. That should give the Sencha Touch team plenty of room to improve and be a significant improvement over jQuery Mobile for most projects.

To me, the biggest downside to jQuery Mobile is the problems with the fixed navigation. They're relying on the browsers to render that, and it's not where it needs to be (even iOS 5, which finally supports fixed headers/footers is a bit off). Other than doing a full javascript re-write of that, they're only hope is that browser makers fix it, and people upgrade. It could take a while for that to happen, if it ever does. I wouldn't wait around for it.

I use Sencha Touch on a daily basis, and have used it since version 1.0 (v2.0rc is now out). Clients love it because it comes close enough to native performance for data presentation apps. I also enjoy writing apps entirely in JS. I have also learned a lot about JS reviewing the source code.

The biggest downsides of Sencha Touch I see are: 1. Initial load. The framework is pretty large, even compressed, but CDN, gzip, and cache.manifest files help

2. Device support. Right now they they only support Android and iOS, but this fits the majority of my target.

3. Learning curve. Coming from a jQuery background it took awhile to understand their approach.

I love jQuery for desktop dev. When I tried a previous version of jQuery mobile the experience was not as good overall as Sencha Touch. Looking at the release notes for JQM 1.1, I will be giving it another try.

Sencha touch is way ahead in my opinion. just check out the kitchen sink demos of Sencha: http://dev.sencha.com/deploy/touch/examples/kitchensink/ and jquery mobile: http://jquerymobile.com/demos/1.1.0-rc.1/

sencha's kitchensink page completely fails to render in my Opera browser.

Is it just my browsers or the last column of buttons in Sencha demo, User Interface-->Buttons seem to be getting clipped on desktop and iphone 4s?

Which device/browser are you referring to? I cannot duplicate the toolbars moving up and down slightly as the page scrolls in safari on a 3GS (iOS 5), with the latest RC demo.

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