Is it possible to access the content(eg. html) loaded into any browser(safari,opera etc.) via another application in iphone or ipad?

I want to make a app,which can read the content which have been loaded into the browser.When users select some region of the webpage,the selected region will be hi开发者_开发百科ghlighted(think of firebug) and my app will read it,process it,then return the modified content to the browser.Is there a solution for implementing it?If it is practicable,how to implement it with phonegap or any of the other mobile frameworks?

Applications on the iPhone run inside a sandbox. Quote from Apple:

For security reasons, iOS restricts each application (including its preferences and data) to a unique location in the file system. This restriction is part of the security feature known as the application's sandbox . The sandbox is a set of fine-grained controls limiting an application's access to files, preferences, network resources, hardware, and so on. Each application has access to the contents of its own sandbox but cannot access other applications' sandboxes.

In conclusion:
It's not possible, certainly not without jailbreak.
Apps cannot interact with other applications, unless Apple provides an API to do so.
In this specific case, Apple does not allow this kind of interaction with Safari or Opera.