A method and apparatus is described for rendering web pages by a wireless device in order to reduce an amount of data transmitted over-the-air to the wireless device. In one embodiment, a method is performed by a server, comprising receiving a markup language document from a web server via a network interface, the markup language document corresponding to a web page. Next, the markup language document is parsed into a number of blocks by a processor, each of the blocks comprising code representing original content of the web page. Then, the processor creates one or more replacement blocks, each of the replacement blocks corresponding to a respective one of the blocks, each of the replacement blocks comprising code representing substituted content of the web page. Some of the blocks and at least one of the replacement blocks are then sent to a wireless device for rendering.