So essentially I am curious as to how to achieve this with my Sencha Touch application. My application includes a log-in form authentication and an aspect of the application allows the user to explore a list of documents/files which are hosted on the same server as the application and is unique to that specific user.

I want the user to be able to select the file within the application(commonly .pdf) and the device browser will choose or present a list of choices of third-party applications which will allow the user to view/edit the document(adobe reader, etc), assuming that Sencha doesn't have a utility which allows the user to view/edit PDF documents. Once the user has made any changes to the document and has closed and "saved" the document, the Sencha Touch application should return, bypassing the log-in form, and these changes should persist on any future occasions of opening the file.

Therefore, if the user chooses to re-open that document, he should see the same document that he had modified previously rather than a newly downloaded copy of that document from the server. What are the possible ways to achieve this, since I am fairly new to web applications?

I know that possibly with a normal mobile application, you can save the information locally on the device and choose to load the information from the device if it is available in storage, but I'm not sure how to achieve this with the Sencha Touch web application.