A web browser sends to a web-application server a request to access a web application. The web server transmits to the web browser a parent document with an inline frame (iframe) containing a Uniform Resource Locator (URL) to an authentication location. In response, a child document is transferred to the web browser. The child document occludes the parent document and presents a user interface for user authentication. Rather than wait until authentication is complete to begin transferring prerequisite files, the web-application server at least partially transfers to the web browser prerequisite files for the web application during the authentication process. This reduces the post-authentication delay involved in transferring prerequisite files, improving the user experience.