The HTTP protocol, as currently used in the World Wide Web, uses a separate TCP connection for each file requested. This adds significant and unnecessary overhead, especially in the number of network round trips required. We analyze the costs of this approach and propose simple modifications to HTTP that, while interoperating with unmodified implementations, avoid the unnecessary network costs. We have implemented our modifications, and our measurements show that they dramatically reduce latencies. We have also investigated the effectiveness of a scheme to mask network latency by prefetching files likely to be requested next, while the user is browsing through the currently displayed page. Our results indicate a significant benefit from prefetching at the cost of an increase in network traffic.