diff --git a/js/rhino/src/org/mozilla/javascript/Context.java b/js/rhino/src/org/mozilla/javascript/Context.java
index 5fe1ab5dd68..6604c5c28f8 100644
--- a/js/rhino/src/org/mozilla/javascript/Context.java
+++ b/js/rhino/src/org/mozilla/javascript/Context.java
@@ -1766,6 +1766,16 @@ public class Context {
      */
     public static final int FEATURE_RESERVED_KEYWORD_AS_IDENTIFIER = 3;
 
+    /**
+     * if hasFeature(FEATURE_TO_STRING_AS_SOURCE) returns true,
+     * calling toString on JS objects gives JS source with code to create an
+     * object with all enumeratable fields of the original object instead of
+     * printing "[object <object-type>]".
+     * By default {@link #hasFeature(int)} returns true only if
+     * the current JS version is set to {@link #VERSION_1_2}.
+     */
+    public static final int FEATURE_TO_STRING_AS_SOURCE = 4;
+
     /**
      * Controls certain aspects of script semantics.
      * Should be overwritten to alter default behavior.
@@ -1774,6 +1784,7 @@ public class Context {
      * @see #FEATURE_NON_ECMA_GET_YEAR
      * @see #FEATURE_MEMBER_EXPR_AS_FUNCTION_NAME
      * @see #FEATURE_RESERVED_KEYWORD_AS_IDENTIFIER
+     * @see #FEATURE_TO_STRING_AS_SOURCE
      */
     public boolean hasFeature(int featureIndex) {
         switch (featureIndex) {
@@ -1798,6 +1809,9 @@ public class Context {
 
             case FEATURE_RESERVED_KEYWORD_AS_IDENTIFIER:
                 return false;
+
+            case FEATURE_TO_STRING_AS_SOURCE:
+                return version == VERSION_1_2;
         }
         // It is a bug to call the method with unknown featureIndex
         throw new IllegalArgumentException();
diff --git a/js/rhino/src/org/mozilla/javascript/NativeArray.java b/js/rhino/src/org/mozilla/javascript/NativeArray.java
index ab1c7813c26..d22aec8ae49 100644
--- a/js/rhino/src/org/mozilla/javascript/NativeArray.java
+++ b/js/rhino/src/org/mozilla/javascript/NativeArray.java
@@ -438,8 +438,8 @@ public class NativeArray extends IdScriptable {
         throws JavaScriptException
     {
         return toStringHelper(cx, thisObj,
-                              cx.getLanguageVersion() == cx.VERSION_1_2,
-                              false);
+            cx.hasFeature(Context.FEATURE_TO_STRING_AS_SOURCE),
+            false);
     }
 
     private static String jsFunction_toLocaleString(Context cx,
diff --git a/js/rhino/src/org/mozilla/javascript/NativeObject.java b/js/rhino/src/org/mozilla/javascript/NativeObject.java
index 7a5f89f75aa..3a982ff17cb 100644
--- a/js/rhino/src/org/mozilla/javascript/NativeObject.java
+++ b/js/rhino/src/org/mozilla/javascript/NativeObject.java
@@ -126,10 +126,10 @@ public class NativeObject extends IdScriptable {
 
     private static String jsFunction_toString(Context cx, Scriptable thisObj)
     {
-        if (cx.getLanguageVersion() != cx.VERSION_1_2)
-            return "[object " + thisObj.getClassName() + "]";
-
-        return toSource(cx, thisObj);
+        if (cx.hasFeature(Context.FEATURE_TO_STRING_AS_SOURCE)) {
+            return toSource(cx, thisObj);
+        }
+        return "[object " + thisObj.getClassName() + "]";
     }
 
     private static String jsFunction_toLocaleString(Context cx,