Also on other question, is how well is it to support the iOS and android device?
Does it work correctly on the device default web browser?
or need to create app just to able to view the page correctly?
If i opt to create app for iOS and android for this JomSocial, does it support?

Hi, Chee.

Thank you for contacting us.
It will work with iOS/Android browsers.
No additional apps or settings are needed ;)

Hi Chee

Let my try to answer your questions and elaborate a little bit on iOS and Android applications

JomSocial's template (every major Joomla! extension has it's own template) is completely responsive. So, based on the screen real estate it will scale to fit the screen, but you must use responsive Joomla! template too.

Now, for the most interesting part, JomSocial does not have a mobile application for any platform, nor we have any plans to develop one anytime soon.
This is because every Joomla! based website is made out of unique extension combination which integrate in JomSocial in one or another way. Or not at all.
In a perfect combination where site would consist from Joomla! and JomSocial alone with nothing else installed, mobile application would probably make sense. However, exact number of such sites at this late date is zero. :)

With that in mind, website applications should really be made for the website as a whole, not only for one extension completely ignoring everything else.
A valid yet illusive question comes to mind. You might say that you're not interested to see the blog or forum in the app, which is okay, but from the technical perspective is a nightmare.
Imagine your blog extension integrating into activity stream of JomSocial and writing the new stream item when there is a new blog post.
Header and content of such stream will probably link to the blog post itself, however, application is made for JomSocial... not for the blog extension.

There are two possibilities we could do
1: Open the browser app and load the content
2. Load the page in a new window within application browser (like facebook does)

None of these possibilities are to our liking, and furthermore this is just a tip of the iceberg of technical difficulties we came across while figuring out how to approach this subject.

So we decide, that mobile applications should be built on site level, including ALL website functionalities, and should never be centralized around single extension.