Read contents of Iframe on webserver

If this is a bad idea and I'm a bad person for thinking it then I'll let it go. But I recently closed my Mint account because all banks do not offer fraud protection to anyone who gives their login credentials to a 3rd party. I was thinking of an application that would avoid that issue by having the user log directly into their account in an iframe and then scraping the contents. My application would not read or store the credentials and the bank's server would be responsible for validating the user. Then when it has validated my application would read and aggregate accounts summaries and transactions and just store that information. I've developed this application as a universal windows application and the webview control. But is it possible to develop it as a web application or are the security measures more restrictive?