A system and method for communication across browser-based applications, and from a crashed application to a web server are disclosed. The system can store structured data in local storage for each instance (e.g., tab, window, frame) of an browser-based application (e.g., website, web application). The data can be structured to group blocks of data according to instances of an application in different tabs. A first session can locate a block of data created by a second session to achieve synchronization between two sessions. In addition, if one session has crashed, data written by that session can be accessed by another session and sent to a web server. In some implementations, a session, when writing to a block of data, can include meta-data for another session or for the web server, such as a timestamp, valid-until time, data-item identifier, etc.