diff --git a/lib/js/runtime.sx b/lib/js/runtime.sx
index 7a2a56a1..6869f88d 100644
--- a/lib/js/runtime.sx
+++ b/lib/js/runtime.sx
@@ -1304,6 +1304,7 @@
       ((= v nil) "object")
       ((= (type-of v) "boolean") "boolean")
       ((= (type-of v) "number") "number")
+      ((= (type-of v) "rational") "number")
       ((= (type-of v) "string") "string")
       ((= (type-of v) "lambda") "function")
       ((= (type-of v) "function") "function")
@@ -1322,6 +1323,7 @@
       ((= (type-of v) "list") "[object Array]")
       ((= (type-of v) "string") "[object String]")
       ((= (type-of v) "number") "[object Number]")
+      ((= (type-of v) "rational") "[object Number]")
       ((= (type-of v) "boolean") "[object Boolean]")
       ((or (= (type-of v) "lambda") (= (type-of v) "function") (= (type-of v) "component"))
         "[object Function]")
@@ -1731,6 +1733,7 @@
       ((= v false) "false")
       ((= (type-of v) "string") v)
       ((= (type-of v) "number") (js-number-to-string v))
+      ((= (type-of v) "rational") (js-number-to-string (exact->inexact v)))
       (else
         (if
           (= (type-of v) "dict")
@@ -2055,6 +2058,14 @@
   js-bitnot
   (fn (a) (- 0 (+ (js-num-to-int (js-to-number a)) 1))))
 
+(define
+  js-numeric-type?
+  (fn (v) (or (= (type-of v) "number") (= (type-of v) "rational"))))
+
+(define
+  js-numeric-norm
+  (fn (v) (if (= (type-of v) "rational") (exact->inexact v) v)))
+
 (define
   js-strict-eq
   (fn
@@ -2062,6 +2073,10 @@
     (cond
       ((and (js-undefined? a) (js-undefined? b)) true)
       ((or (js-undefined? a) (js-undefined? b)) false)
+      ((and (js-numeric-type? a) (js-numeric-type? b))
+        (let
+          ((an (js-numeric-norm a)) (bn (js-numeric-norm b)))
+          (if (or (js-number-is-nan an) (js-number-is-nan bn)) false (= an bn))))
       ((not (= (type-of a) (type-of b))) false)
       (else
         (if (or (js-number-is-nan a) (js-number-is-nan b)) false (= a b))))))
@@ -2076,10 +2091,10 @@
       ((js-strict-eq a b) true)
       ((and (= a nil) (js-undefined? b)) true)
       ((and (js-undefined? a) (= b nil)) true)
-      ((and (= (type-of a) "number") (= (type-of b) "string"))
-        (= a (js-to-number b)))
-      ((and (= (type-of a) "string") (= (type-of b) "number"))
-        (= (js-to-number a) b))
+      ((and (js-numeric-type? a) (= (type-of b) "string"))
+        (= (js-numeric-norm a) (js-to-number b)))
+      ((and (= (type-of a) "string") (js-numeric-type? b))
+        (= (js-to-number a) (js-numeric-norm b)))
       ((= (type-of a) "boolean") (js-loose-eq (js-to-number a) b))
       ((= (type-of b) "boolean") (js-loose-eq a (js-to-number b)))
       ((and (dict? a) (contains? (keys a) "__js_string_value__"))
diff --git a/plans/js-on-sx.md b/plans/js-on-sx.md
index bbcb2e59..80117c6c 100644
--- a/plans/js-on-sx.md
+++ b/plans/js-on-sx.md
@@ -158,6 +158,8 @@ Each item: implement → tests → update progress. Mark `[x]` when tests green.
 
 Append-only record of completed iterations. Loop writes one line per iteration: date, what was done, test count delta.
 
+- 2026-05-09 — **Rational handling in `js-typeof` / `js-to-string` / `js-strict-eq` / `js-loose-eq` / `Object.prototype.toString`.** Followup to the `js-to-number` fix. SX rationals were leaking into other paths: `typeof 1/2` returned `"object"` (should be `"number"`), `String(1/2)` fell into the dict branch and returned `"[object Object]"`, and `1/2 === 0.5` was false because strict-eq compared types and `"rational"` ≠ `"number"`. Added rational arms to `js-typeof` and `js-object-tostring-class`, normalised rationals via `(exact->inexact)` in `js-to-string`'s number branch, and introduced a `js-numeric-type?` / `js-numeric-norm` pair that lets strict-eq and loose-eq treat both numeric kinds uniformly. Result: language/expressions/strict-equals 16/22 → 19/22; Math 30/30 confirmed (no regression — but it never had one). Object/Array/Map unchanged. conformance.sh: 148/148.
+
 - 2026-05-09 — **`js-to-number` now coerces SX rationals via `exact->inexact`.** SX `(/ 59 16)` returns the rational `59/16` with `(type-of)` `"rational"` — not `"number"` — so `js-to-number` was falling through to the dict branch and ultimately returning `0`. That broke any path that did integer-divide intermediate math (e.g. `js-hex-2` for percent-encoding: `(js-math-trunc (/ 59 16))` was returning 0, so `encodeURIComponent(";")` produced `"%0B"` instead of `"%3B"`). Added a `((= (type-of v) "rational") (exact->inexact v))` clause in `js-to-number` between the existing `"number"` and `"string"` branches. Result: built-ins/encodeURIComponent 9/30 → 15/30, built-ins/encodeURI 22/60 → 28/60, built-ins/decodeURI 11/60 → 20/60. Object/Array unchanged. conformance.sh: 148/148.
 
 - 2026-05-09 — **`parseFloat("+")` / `parseFloat("-")` / `parseFloat(".")` return NaN (were returning 0).** `js-float-prefix-end` happily consumed leading `+`/`-` and dot characters even with no digits — and `js-parse-num-safe` of those characters returned 0. Per spec, the prefix must contain at least one digit. Added a `js-str-has-digit?` walker called between `js-float-prefix-end` and `js-parse-num-safe`; if no digit is present in the consumed slice, return NaN. Result: built-ins/parseFloat 20/30 → 23/30, built-ins/parseInt 22/30 → 24/30. Number unchanged. conformance.sh: 148/148.