What are two major considerations when designingthe user interface for browser-based systems?

Browser-based systems must always be thinking about response time since all the components and images must be loaded over the Internet. Too much data causes slow load times. (There are many examples of poor design. For example, many news sites take forever to load because of too much data and not enough server capacity or network capacity.)
 The other issue is compatibility between browsers. IE, Chrome, Firefox, Safari each have different techniques and display methods. A good design on one browser may perform very poorly on another one.