The WebSocket interface's onerror event handler property is a function which gets called when an error occurs on the WebSocket.

You can also add an error event handler using addEventListener().


webSocket.onerror = eventHandler;


A function or EventHandler which is executed whenever an error event occurs on the WebSocket connection.


webSocket.onerror = function(event) {
  console.error("WebSocket error observed:", event);


Specification Status Comment
HTML Living Standard
The definition of 'WebSocket: onerror' in that specification.
Living Standard Initial definition

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
onerrorChrome Full support YesEdge Full support 12Firefox Full support YesIE ? Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesFirefox Android Full support YesOpera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yes


Full support  
Full support
Compatibility unknown  
Compatibility unknown