A Fast Synchronization Mechanism for Collaborative Web Applications based on HTML5
片山真也, 合田拓史, 白松俊, 大囿忠親, 新谷虎松


We are developing a collaborative web application for editing PDF documents using web browsers. Our system enables users to edit the same document in real-time. Users can share annotations on papers in real-time on web browsers. One of the advantages of our system is very high availability. Users only need to have their own web browsers. To improve the usability of our system, we need to consider synchronization delay. Synchronization delay consists of network delay and drawing delay. Our system draws PDF files by using JavaScript, it is not fast enough for real-time collaborative editing. We propose a new synchronization method using Canvas API to reduce drawing delay. We show how to implement a real-time collaborative editing system by using the method. We present evaluation results that indicate the method is suited for collaborative web applications.