1. An apparatus comprising: at least one processor; and memory coupled to said at least one processor storing: a markup language document containing: a first instance of a markup language element having an attribute with a first, platform-independent value; a second instance of said markup language element having said attribute with a second, platform-specific value, wherein said platform is a platform to which an instance of said markup language element is to be deployed; and an indicator that said second value overrides said first value; and machine-executable code which, when executed by the at least one processor, replaces both of said first instance and said second instance with a single instance of said markup language element having said attribute with said second value.