Usually it's the other way around, people write webpages for IE and forget the other browsers. I know next to nothing about building webpages, but it looks like you need script to identify the browser, then write about 4 different websites for the different implementations to make them all look the same.
Actually, you use one script to interogate the browser and one set of webpages to inclose your data collected by one of several methods and then write 4 or 5 different style sheets to render the webpages appropriately for the browser in question.