The World Wide Web has become a new and powerful medium. However, applications on the Web are currently not fully multimedia supported. This is mainly because that the synchronization in the Web environment can be extremely complex, as the network infrastructure on which the Web is based provides no guarantee of real time data transfer, especially for large media, such as audio and video. In this article, weak synchronization is introduced as an efficient approach to specify temporal relationships among objects in a multimedia document to gain the best presentation performance. This approach provides a new modeling mechanism that can specify the precise as well as imprecise temporal relationships among involved objects. Specifications on inter-media synchronization, such as strict synchronization method and loose synchronization method, are also included in the approach.