We save and display files that are e-mailed to our webservices. Sometimes we want to let users preview the files. For images and pdf:s we can easily scale them down to an appropriate size(for pdf:s we use iframes). 

However sometimes the e-mailed content contain html. Is there some way to scale it down to fit within the size of an iframe? Like widt=device-width scale=1 for mobile? We can accept a fixed width if necessary, however, we don't know the width of the content.