Develop Reference

How to provide JavaScript library for mobile native apps?

I am not a mobile developer, hence please excuse me for incorrect assumptions, if any
I have a library which users want to integrate in their native mobile apps. It is written in JavaScript, but I don't want to rewrite for Android and iOS. Hence what I need is some way that this JavaScript library can be used in native apps. Following two ways look promising:
WebViews: The JS files would reside locally and webview will be used to run them
NativeScript: NativeScript allows you to create native apps from JavaScript. But I didn't find anything which suggests that I can create native library too. Can this be used in any way?

You might be looking for React Native
It is a Javascript framework, and when you write your code, most of the time, you can use the same code for iOS and Android. It is a relatively new framework, but can be very powerful for rapid cross-development, but (obviously) has its trade-offs.

Can I use EmberJS or other frameworks without gettting its server up?

I want a javascript framework which has features like below:
MV*
Well structured
Html file as template
Rendering fast(maybe virtual dom?)
Combine and compatible with other plugins or libraries
Edit on tablet IDE apps and view in browser immediately by refreshing page after I changed code
When I am at home, I use PC to develop my client-side(or front-end) applications.
When go out, I use my tablet(I have no note PC), so I want to develop my applications outside.
*There are some excellent IDE apps on the Android Market.
Before I know Ember, I have been using pure javascript(jquery) + css + html to develop client-side application for daily practices or work.
But recently, when I began to learn EmberJS, a Javascript MVC framwork, I am lost.
It seems that EmberJS have to get its own server up to compile something, which generate static contents for browser rendering.
I just want to get my client-side code(files) rendering in the browser, but why I have to 'run' it as if I get apache started to serve as a php back-end.
I have googled hundreds of pages to find a solution, nothing expected result discovered.
Including Angular, backbone or any other popular Javascript MV* frameworks, they all must compile there applications.
Is there anyone who has encountered this situation?
Then any advice, please?

Increasingly most Javascript frameworks are shifting to doing a "compile step" as part of using them. This allows you to do a variety of changes to your Javascript files, which in turn makes it easier for you as a developer. An example of this is that you can use ES2015 classes and then have your compile step "transpile" them to older Javascript that will work in all browsers.
The side effect of this though is that you need to have npm running on your computer to be able to do this well.
If you really don't want to have the compile step, then I would suggest looking at VueJS. It's the only recent Javascript framework that allows working with simple non-compiled JS files. But you'all be missing out on some of the best changes to Javascript as a result (ES2015 has made life much better)

Finally, I found a nice solution(framework) that is Durandal.
Really, pure HTML+Javascript without built and server up(anyhow, a web server needed if I wanted to publish it in my hosted web server).
.html extension and designer friendly.
I can upload its source files directly in to S3 and browse the html pages.
Just found some nice examples with well structured project on github is here.
And I can work smoothly with my dear designer friends.
Though its next generation Aurelia will also be built and serve it up like Ember or others, but the current generation is enough for me.
Hope those one got help from this;)

how do i implement a google doc-like app on mobile?

I'm currently working on a project similar to google docs. Basically, it allows
multiple users to edit word documents concurently in a web browser. I've been
working extensively in pure javascript nodejs and socket.io. The web based
text editor was written from scratch using HTML5, CSS and Javascript. I handled
Operational Transformation(OT) with shareJS(server & client library that allows
realtime editing).
The challenge I'm having now is with mobile development, where I typically want
to develop for both android and iOS. I've been unsure about the right workflow and
technical decisions to make. Below is what has been going through my mind:
How do I incorporate my javascript application into a native iOS/Android app? Should
I just build an exact clone of what I have on the web from scratch? I mean build a
replica of my web implementation in iOS(Swift)/Android(Java). Of course this would mean
re-writing my text editor and OT scripts from scratch in the native language. Does that
make sense?
I know of NativeScript and phonegap. But then, when it comes to mobile, I prefer leaning
towards the native language. Is there a way to wrap my javascript into Swift/Android in
order to call my javascript functions?
Have been thinkin about this for weeks now, pondering over how to go about this. I think i need suggestions,
thoughts and advice from other frames of reference. Thanks in advance

javascript library in my Java project?

I am working on a project in Java that involves designing a speedometer. I am looking for any libraries that I can possibly use. However, I found a lot of such "gauge libraries" for javascript. Is there any way I can implement this javascript library in my project Java?

I think its all depend on the architecture of your application, for example building a reactive application on the JVM, using a technology like Vert.x will allow you to do that.
I strongly recommend vert.x, you will find a lot of magic there

Desktop like web apps and JS frameworks?

I am still learning javascript and the more i learn the more i ask myself why do i need to learn a js framework like cappuccino, sproutcore, qooxdoo, smartclient etc...? The learning curve for these frameworks is steep, also wouldn't it be better to just make use of JavaScript libraries?
Take note, that my objective is to create desktop like web apps. Thanks in advance for any good view points!

Desktop apps are built with frameworks that are of the same quality as those from SproutCore, Cappuccino, etc.
If you want to build desktop quality apps with true MVC architecture you can either write your own framework on top of a library, or start with a framework someone else has written. (SproutCore was originally built on top of jQuery for example)
The best part of a true framework is that the build tools can include only the pieces needed to run your app resulting in very small code with rapid load times.

Seeing as you are still learning Javascript, I would suggest that you continue to work with Javascript, and try out tools like jQuery, and then depending on the individual application you are working on, evaluate whether you need to use a more full featured desktop style Javascript framework at that time - something that will require a knowledge of jQuery/Prototype/etc to evaluate.

IMHO, those JS frameworks you mentioned are overrated bloatware.
I would wholeheartedly recommend that you learn JQuery instead.
It is a much more minimallistic and elegant framework.
Also, by the time IE 9 finally ships earlier next year, all the browsers
will be supporting most of the HTML5 standard, including offline storage and
websockets, making such complex frameworks completely unnecesary.