Listings template for on-line auctions
Big issue: you can create your own replace function as something like a recursive array iterator. It should be quite easy, but there might be some performance drawbacks if used on long strings, but the code above is not the case. Also you probably better off drop the regexp, unless search() function is allowed.
As of css there are reset stylesheets/boilerplates to start with and there are also preprocessors like sass or less, to help you create a more structured stylesheet.
Cross browser compatibility is always depending on your target audience, but generally speaking it's enough if you support the last 2 version of all major browsers and try to keep it at least "minimally functional" for the rest if possible.