How an mobile compatible website handles the performance?
As we are now a days fond of bootstrap css which helps in compatiblity. My question is how exactly it deals with the loading as we have more load to the desktop apps and less to mobile. So according to me the css is handling through @media-screen object stylings with toggling of display and alignment. But even if we control the display from client side css or js. Server side will do its task of loading, So whether both desktop website and mobile website are taking the same amount of dataload.
Why am i asking this is if there is same amount of dataload, ill rather choose Android app instead of bootstrap for the fast performance.
Its important to remember that Bootstrap is a client side framework for helping to create responsive websites. You're right in that the same amount of stuff will be sent down the pipe regardless of the device that is used. This is true for any website that just uses client side frameworks to render for mobiles, such as jQuery Mobile.
If your application is big and complex then you may be better off serving up a different page for those mobile devices using Server side technologies. We use the Microsoft .Net stack which can render different views/scripts/css depending on a number of parameters to do with device. You can still use the Bootstrap framework, but maybe render less in the DOM, or have a smaller version of Bootstrap. You could even try a different framework such as the super tiny Pure framework.
Another alternative like you said is to build a native app. This will generally (if you make it right) be faster that what you can achieve in the browser, but you need to be careful that it is actually providing something useful to the user to encourage them to install it. If you are just using it to make it easier to make your website then you're doing it wrong, but if you are building a highly complex app that can leverage some of the extra functionality you can use in a native app then it may be a good way round it.
Without a real question there isn't a huge amount more than my own experience to draw on here, and there is no real right answer to how you go about it, but in answer to the question of how it deals with loading, client side frameworks can't really change what is being loaded without serious customisation or using some server side technology to deliver different pages altogether.