Embodiments of the present invention provide techniques for tracking the lifecycles of client-side browser windows in the context of a web application. In one set of embodiments, a server component of a web application can receive a request originating from a client-side browser window, where the request includes a resource locator (e.g., a URL) and a window identifier. In response, the server component can send a script to the window for retrieving the window's actual identifier/name. Based on the actual identifier returned by the script and the window identifier included in the initial request, the server component can determine whether the window is a new window or an existing window and can process the request as appropriate.