![]() A generic error has fired but because Xojo Web was working fine prior to the users tab being suspended it is not aware of connectivity issues. Sadly, with Xojo’s SSE implementation there is no recognition that the connection to the server has been closed. In the old XMLHttpRequest handlers this was recognized and if a session is no longer available on the server then the browser reloads itself. When a users session times out the users browser needs to be reloaded so a new session can be created and use continued. This is great but unfortunately there is a bug. In Xojo 2018r1+ the web framework now defaults to SSE as opposed to XMLHttpRequest for all devices (except Firefox). This helps web applications respond faster to changes as building up a request is very expensive in regards to latency and when generating tons of events can really impair web application performance. They provide a persistent connection between the browser and server in either bidirectional or unidirectional capacities. Since the inception of AJAX however many new technologies like WebSocket’s and Server-sent Events (SSE) have been released. This is the browser provided class that enables all AJAX interactivity on the web. ![]() In Xojo 2017 and before this was not a problem because the entire communication stack between the browser and server was built on XMLHttpRequest. This severs the link between the user application and the Xojo Web server. Behind the scenes the iOS or Android operating system suspends the javascript execution of the browser tab. This is most prevalent on mobile devices when the user is interacting with your Xojo Web app and then moves on to something else. As reported by Ralph Alvy and several others on the forums ( ) and in Feedback (53291) Xojo web applications built in Xojo 2018r1+ can lock up with no visual indication or recovery.
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