diff --git a/src/test/java/org/htmlunit/general/ElementOwnPropertySymbolsTest.java b/src/test/java/org/htmlunit/general/ElementOwnPropertySymbolsTest.java
index 128b3c67657..05d20b1cda3 100644
--- a/src/test/java/org/htmlunit/general/ElementOwnPropertySymbolsTest.java
+++ b/src/test/java/org/htmlunit/general/ElementOwnPropertySymbolsTest.java
@@ -3743,4 +3743,34 @@ public void urlSearchParams() throws Exception {
     public void namedNodeMap() throws Exception {
         testString("", "element.attributes");
     }
+
+    /**
+     * Test MutationObserver.
+     *
+     * @throws Exception if the test fails
+     */
+    @Test
+    @Alerts(CHROME = "Symbol(Symbol.toStringTag) [MutationObserver]",
+            EDGE = "Symbol(Symbol.toStringTag) [MutationObserver]",
+            FF = "Symbol(Symbol.toStringTag) [MutationObserver]",
+            FF_ESR = "Symbol(Symbol.toStringTag) [MutationObserver]",
+            IE = "exception")
+    public void mutationObserver() throws Exception {
+        testString("", "new MutationObserver(function(m) {})");
+    }
+
+    /**
+     * Test WebKitMutationObserver.
+     *
+     * @throws Exception if the test fails
+     */
+    @Test
+    @Alerts(CHROME = "Symbol(Symbol.toStringTag) [MutationObserver]",
+            EDGE = "Symbol(Symbol.toStringTag) [MutationObserver]",
+            FF = "exception",
+            FF_ESR = "exception",
+            IE = "exception")
+    public void webKitMutationObserver() throws Exception {
+        testString("", "new WebKitMutationObserver(function(m) {})");
+    }
 }
diff --git a/src/test/java/org/htmlunit/general/ElementPropertiesTest.java b/src/test/java/org/htmlunit/general/ElementPropertiesTest.java
index 6ba8b865642..3e12474f97a 100644
--- a/src/test/java/org/htmlunit/general/ElementPropertiesTest.java
+++ b/src/test/java/org/htmlunit/general/ElementPropertiesTest.java
@@ -9335,4 +9335,34 @@ public void urlSearchParams() throws Exception {
     public void namedNodeMap() throws Exception {
         testString("", "element.attributes");
     }
+
+    /**
+     * Test MutationObserver.
+     *
+     * @throws Exception if the test fails
+     */
+    @Test
+    @Alerts(CHROME = "disconnect(),observe(),takeRecords()",
+            EDGE = "disconnect(),observe(),takeRecords()",
+            FF = "disconnect(),observe(),takeRecords()",
+            FF_ESR = "disconnect(),observe(),takeRecords()",
+            IE = "disconnect(),observe(),takeRecords()")
+    public void mutationObserver() throws Exception {
+        testString("", "new MutationObserver(function(m) {})");
+    }
+
+    /**
+     * Test WebKitMutationObserver.
+     *
+     * @throws Exception if the test fails
+     */
+    @Test
+    @Alerts(CHROME = "disconnect(),observe(),takeRecords()",
+            EDGE = "disconnect(),observe(),takeRecords()",
+            FF = "exception",
+            FF_ESR = "exception",
+            IE = "exception")
+    public void webKitMutationObserver() throws Exception {
+        testString("", "new WebKitMutationObserver(function(m) {})");
+    }
 }