diff --git a/src/dom/exceptions.zig b/src/dom/exceptions.zig
index b7fc8460..63cd4104 100644
--- a/src/dom/exceptions.zig
+++ b/src/dom/exceptions.zig
@@ -91,6 +91,12 @@ pub const DOMException = struct {
             error.InvalidNodeType => "InvalidNodeTypeError",
             error.DataClone => "DataCloneError",
             error.NoError => unreachable,
+
+            // custom netsurf error
+            error.UnspecifiedEventType => "UnspecifiedEventTypeError",
+            error.DispatchRequest => "DispatchRequestError",
+            error.NoMemory => "NoMemoryError",
+            error.AttributeWrongType => "AttributeWrongTypeError",
         };
     }
 
@@ -124,6 +130,12 @@ pub const DOMException = struct {
             error.InvalidNodeType => 24,
             error.DataClone => 25,
             error.NoError => unreachable,
+
+            // custom netsurf error
+            error.UnspecifiedEventType => 128,
+            error.DispatchRequest => 129,
+            error.NoMemory => 130,
+            error.AttributeWrongType => 131,
         };
     }
 
diff --git a/src/netsurf.zig b/src/netsurf.zig
index e6e07598..65e64d63 100644
--- a/src/netsurf.zig
+++ b/src/netsurf.zig
@@ -339,6 +339,12 @@ pub const DOMError = error{
     Timeout,
     InvalidNodeType,
     DataClone,
+
+    // custom netsurf error
+    UnspecifiedEventType,
+    DispatchRequest,
+    NoMemory,
+    AttributeWrongType,
 };
 
 const DOMException = c.dom_exception;
@@ -363,6 +369,13 @@ fn DOMErr(except: DOMException) DOMError!void {
         c.DOM_INVALID_ACCESS_ERR => DOMError.InvalidAccess,
         c.DOM_VALIDATION_ERR => DOMError.Validation,
         c.DOM_TYPE_MISMATCH_ERR => DOMError.TypeMismatch,
+
+        // custom netsurf error
+        c.DOM_UNSPECIFIED_EVENT_TYPE_ERR => DOMError.UnspecifiedEventType,
+        c.DOM_DISPATCH_REQUEST_ERR => DOMError.DispatchRequest,
+        c.DOM_NO_MEM_ERR => DOMError.NoMemory,
+        c.DOM_ATTR_WRONG_TYPE_ERR => DOMError.AttributeWrongType,
+
         else => unreachable,
     };
 }