Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

The MediaRecorder.onwarning event handler (part of the MediaRecorder API) handles the recording warning event, allowing you to run code in response to non-fatal errors being thrown during media recording via a MediaRecorder (errors that don't halt recording).


mediaRecorder.onwarning = function(event) { ... }
mediaRecorder.addEventListener('warning', function(event) { ... })



  mediaRecorder.onwarning = function(e) {
    console.log("A warning has been raised: " + e.message);




Contains information about the error that occurred.

Browser compatibility

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See also