How to Detect Registered Protocol Handlers in a Browser?

Detecting Browser's Protocol Handlers

Custom URL protocol handlers are powerful tools for extending browser functionality. However, handling cases where the handler is not installed can be challenging.

One approach to detecting registered protocol handlers in a browser is to exploit its behavior. By attaching an event listener to a custom protocol link that triggers a timer and window blur event, we can infer the presence or absence of the handler.

If the browser successfully opens the application associated with the protocol, it will take focus, causing the window to blur and the timer to be cleared. Conversely, if the blur event fires, it indicates that the application was not launched, suggesting that the handler is not installed.

While this method is rather unconventional and prone to false positives or negatives, it provides a possible workaround for gracefully handling situations where the custom protocol handler is missing.

The above is the detailed content of How to Detect Registered Protocol Handlers in a Browser?. For more information, please follow other related articles on the PHP Chinese website!