diff --git a/core/rfb.js b/core/rfb.js
index 76d13f0a..f8fc4e71 100644
--- a/core/rfb.js
+++ b/core/rfb.js
@@ -183,22 +183,13 @@ export default class RFB extends EventTargetMixin {
         this._sock = new Websock();
         this._sock.on('message', this._handle_message.bind(this));
         this._sock.on('open', () => {
-            if (typeof options.onSocketOpen === "function") {
-                let errorDescription;
-                try {
-                    errorDescription = options.onSocketOpen(this._sock._websocket);
-                } catch (e) {
-                    return this._fail("onSocketOpen callback failed: " + e.stack);
-                }
-                if (errorDescription) {
-                    return this._fail("onSocketOpen callback failed: " + errorDescription);
-                }
-            }
-
             if ((this._rfb_connection_state === 'connecting') &&
                 (this._rfb_init_state === '')) {
                 this._rfb_init_state = 'ProtocolVersion';
                 Log.Debug("Starting VNC handshake");
+                if (!this.dispatchEvent({type: 'webSocketOpen', ws: this._sock._websocket})) {
+                    return this._fail("webSocketOpen event handler has prevented the further execution");
+                }
             } else {
                 this._fail("Unexpected server connection while " +
                            this._rfb_connection_state);
diff --git a/tests/test.rfb.js b/tests/test.rfb.js
index 30a5b5ff..f70fbf42 100644
--- a/tests/test.rfb.js
+++ b/tests/test.rfb.js
@@ -1408,34 +1408,21 @@ describe('Remote Frame Buffer Protocol Client', function () {
                 expect(client._sock).to.have.sent(new Uint8Array([0]));
             });
 
-            it('should fail if onSocketOpen callback returns a failure description', function () {
-                const rfb = new RFB(container, 'wss://host:8675', { onSocketOpen: () => 'Something went wrong' });
-                clock.tick();
-                sinon.spy(rfb, "_fail");
-                rfb._sock._websocket._open();
-                expect(rfb._fail).to.have.been.calledOnce;
+            it('should fail if webSocketOpen event handler prevents execution', function () {
+                const client = make_rfb();
+                client.addEventListener('webSocketOpen', (event) => {
+                    event.defaultPrevented = true;
+                });
+                sinon.spy(client, "_fail");
+                client._sock._websocket._open();
+                expect(client._fail).to.have.been.calledOnce;
             });
 
-            it('should fail if onSocketOpen callback throws an exception', function () {
-                const rfb = new RFB(container, 'wss://host:8675', { onSocketOpen: () => { throw new Error(); } });
-                clock.tick();
-                sinon.spy(rfb, "_fail");
-                rfb._sock._websocket._open();
-                expect(rfb._fail).to.have.been.calledOnce;
-            });
-
-            it('should pass if onSocketOpen callback succeeds', function () {
-                const client = make_rfb('wss://host:8675', { onSocketOpen: (ws) => {
-                    expect(!!ws).to.be.true;
-                }});
-                client._rfb_connection_state = 'connecting';
-                client._rfb_init_state = 'SecurityResult';
-                client._sock._websocket._receive_data(new Uint8Array([0, 0, 0, 0]));
-                expect(client._rfb_init_state).to.equal('ServerInitialisation');
-            });
-
-            it('should pass if onSocketOpen callback is not a function', function () {
-                const client = make_rfb('wss://host:8675', { onSocketOpen: 123 });
+            it('should pass if webSocketOpen event handler passes', function () {
+                const client = make_rfb();
+                client.addEventListener('webSocketOpen', (event) => {
+                    expect(!!event.ws).to.be.true;
+                });
                 client._rfb_connection_state = 'connecting';
                 client._rfb_init_state = 'SecurityResult';
                 client._sock._websocket._receive_data(new Uint8Array([0, 0, 0, 0]));