diff --git a/source/quickjs.c b/source/quickjs.c
index d78fe3cb..38a5c085 100644
--- a/source/quickjs.c
+++ b/source/quickjs.c
@@ -929,7 +929,6 @@ struct JSObject {
             uint8_t is_constructor : 1; /* TRUE if object is a constructor function */
             uint8_t has_immutable_prototype : 1; /* cannot modify the prototype */
             uint8_t tmp_mark : 1; /* used in JS_WriteObjectRec() */
-            uint8_t is_HTMLDDA : 1; /* specific annex B IsHtmlDDA behavior */
             uint16_t class_id; /* see JS_CLASS_x */
         };
     };
@@ -5058,7 +5057,6 @@ static JSValue JS_NewObjectFromShape(JSContext *ctx, JSShape *sh, JSClassID clas
     p->is_constructor = 0;
     p->has_immutable_prototype = 0;
     p->tmp_mark = 0;
-    p->is_HTMLDDA = 0;
     p->weakref_count = 0;
     p->u.opaque = NULL;
     p->shape = sh;
@@ -10399,24 +10397,6 @@ static JSValue JS_ToPrimitive(JSContext *ctx, JSValueConst val, int hint)
     return JS_ToPrimitiveFree(ctx, JS_DupValue(ctx, val), hint);
 }
 
-void JS_SetIsHTMLDDA(JSContext *ctx, JSValueConst obj)
-{
-    JSObject *p;
-    if (JS_VALUE_GET_TAG(obj) != JS_TAG_OBJECT)
-        return;
-    p = JS_VALUE_GET_OBJ(obj);
-    p->is_HTMLDDA = TRUE;
-}
-
-static inline BOOL JS_IsHTMLDDA(JSContext *ctx, JSValueConst obj)
-{
-    JSObject *p;
-    if (JS_VALUE_GET_TAG(obj) != JS_TAG_OBJECT)
-        return FALSE;
-    p = JS_VALUE_GET_OBJ(obj);
-    return p->is_HTMLDDA;
-}
-
 static int JS_ToBoolFree(JSContext *ctx, JSValue val)
 {
     uint32_t tag = JS_VALUE_GET_TAG(val);
@@ -10463,14 +10443,8 @@ static int JS_ToBoolFree(JSContext *ctx, JSValue val)
             return ret;
         }
     case JS_TAG_OBJECT:
-        {
-            JSObject *p = JS_VALUE_GET_OBJ(val);
-            BOOL ret;
-            ret = !p->is_HTMLDDA;
-            JS_FreeValue(ctx, val);
-            return ret;
-        }
-        break;
+      JS_FreeValue(ctx, val);
+      return 1;
     default:
         if (JS_TAG_IS_FLOAT64(tag)) {
             double d = JS_VALUE_GET_FLOAT64(val);
@@ -14898,15 +14872,7 @@ static no_inline __exception int js_eq_slow(JSContext *ctx, JSValue *sp,
         }
         goto redo;
     } else {
-        /* IsHTMLDDA object is equivalent to undefined for '==' and '!=' */
-        if ((JS_IsHTMLDDA(ctx, op1) &&
-             (tag2 == JS_TAG_NULL || tag2 == JS_TAG_UNDEFINED)) ||
-            (JS_IsHTMLDDA(ctx, op2) &&
-             (tag1 == JS_TAG_NULL || tag1 == JS_TAG_UNDEFINED))) {
-            res = TRUE;
-        } else {
-            res = FALSE;
-        }
+        res = FALSE;
         JS_FreeValue(ctx, op1);
         JS_FreeValue(ctx, op2);
     }
@@ -15254,9 +15220,7 @@ static __exception int js_operator_typeof(JSContext *ctx, JSValueConst op1)
         {
             JSObject *p;
             p = JS_VALUE_GET_OBJ(op1);
-            if (unlikely(p->is_HTMLDDA))
-                atom = JS_ATOM_undefined;
-            else if (JS_IsFunction(ctx, op1))
+            if (JS_IsFunction(ctx, op1))
                 atom = JS_ATOM_function;
             else
                 goto obj_type;
@@ -19277,6 +19241,7 @@ static JSValue JS_CallInternal(JSContext *caller_ctx, JSValueConst func_obj,
             /* XXX: could merge to a single opcode */
         CASE(OP_typeof_is_undefined):
             /* different from OP_is_undefined because of isHTMLDDA */
+            /* HTMLDDA removed, so can merge */
             if (js_operator_typeof(ctx, sp[-1]) == JS_ATOM_undefined) {
                 goto free_and_set_true;
             } else {
diff --git a/source/quickjs.h b/source/quickjs.h
index 7340d7dc..b773bb04 100644
--- a/source/quickjs.h
+++ b/source/quickjs.h
@@ -924,9 +924,6 @@ void JS_SetCanBlock(JSRuntime *rt, JS_BOOL can_block);
 void JS_SetStripInfo(JSRuntime *rt, int flags);
 int JS_GetStripInfo(JSRuntime *rt);
 
-/* set the [IsHTMLDDA] internal slot */
-void JS_SetIsHTMLDDA(JSContext *ctx, JSValueConst obj);
-
 typedef struct JSModuleDef JSModuleDef;
 
 /* return the module specifier (allocated with js_malloc()) or NULL if