diff --git a/bug_test.go b/bug_test.go
index 1c63cb4..6a2d216 100644
--- a/bug_test.go
+++ b/bug_test.go
@@ -675,3 +675,17 @@ func Test_S15_1_2_2_A2_T10(t *testing.T) {
         `, true)
 	})
 }
+
+func Test_S15_1_2_3_A2_T10(t *testing.T) {
+	tt(t, func() {
+		test, _ := test()
+
+		test(`
+			parseFloat("\u180E" + "1.1") === parseFloat("1.1");
+        `, true)
+
+		test(`
+			parseFloat("\u180E" + "\u180E" + "\u180E" + "1.1") === parseFloat("1.1");
+        `, true)
+	})
+}
diff --git a/builtin.go b/builtin.go
index b918498..256ee3c 100644
--- a/builtin.go
+++ b/builtin.go
@@ -153,7 +153,8 @@ var parseFloat_matchValid = regexp.MustCompile(`[0-9eE\+\-\.]|Infinity`)
 
 func builtinGlobal_parseFloat(call FunctionCall) Value {
 	// Caveat emptor: This implementation does NOT match the specification
-	input := strings.TrimSpace(call.Argument(0).string())
+	input := strings.Trim(call.Argument(0).string(), builtinString_trim_whitespace)
+
 	if parseFloat_matchBadSpecial.MatchString(input) {
 		return NaNValue()
 	}