iFrames, do they even still exist?
Well integration with systems isn't aways APIs, XML and JSON magically working in harmony. Some times you have to integrate a web app into another site as quickly as possible, maintaining the sparation to avoid unpleasant upgrade costs.
iFrames intially appear to be a great solution, but they do present a number of horrible problems. The worst offender IMO is the height property. Why on earth does setting the height to auto or 100% not allow the iFrame to fit the content it contains automatically? This would seem the most logical and common option, who likes scroll bars inside scroll bars? Well I guess those higher powers that design specifications seemed to decide that scrollbars are great.
If anyone knows a pure HTML, CSS method I would love to hear it.