Someone send me an email asking why my website's HTML content was broken and had me baffled for a while. Following up on the issue I manage to get the HTML code he was seeing with his browser, where the HTML content was indeed mangled. Initially I assumed he was accessing the server via a proxy but after some investigation I concluded everything was good, there was no unknown man in the middle.

So what happened the visitor was accessing the site using an ISP who provided wireless services. They are forcing some sort of mini-compression to the HTML content downloaded to browsers to give you a better understanding of what is all about you can search for

bmi_SafeAddOnload

Ok now the HTML code that was mangled had all the resource stylesheets, javascripts etc as part of the HTML page. Whitespace was stripped, and copyright headers of the stylesheets and javascripts were removed. Some of the ajax scripts were broken so the pages of course did not work as expected. I suspect this happened because the copyright text was presented as CSS and Javascript comments and the whatever filter in use by the ISP, just erased every comment.

So let alone striping the HTML and javascript content breaking pages, they strip out the copyright headers from the stylesheets, html pages, javascripts etc., so the user doesn't know to whom the content belongs to really. Does anyone has any experience about it or knows if that is illegal?

Just to avoid any confusion this is not related with browser settings or firewalls or router settings. Its how the service is setup from what I learned.