X3D supports a variety of media types to be used in 3D scenes like images, videos or other X3D models. A scene can dynamically load and replace this media during runtime, but since there is no way to communicate directly with outside sources like a server, all data sources need to be known in advance. This problem is usually solved by using interfaces like SAI, which allow external applications to modify the current scene. But this solution makes it necessary to set up all the communication via SAI and have the external application communicate with a server. In this paper, we will show how XMLHttpRequest, an object common in web browsers, can be used to handle the communication from within the X3D Browser. We will show how well this approach fits into the X3D environment and how easy this can be implemented in an X3D Browser. Afterwards, some examples will show the benefits in real applications and how easy this solution is to use.