diff --git a/fpdfsdk/javascript/public_methods_unittest.cpp b/fpdfsdk/javascript/public_methods_unittest.cpp
new file mode 100644
index 0000000..ace0920
--- /dev/null
+++ b/fpdfsdk/javascript/public_methods_unittest.cpp
@@ -0,0 +1,51 @@
+// Copyright 2016 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "fpdfsdk/javascript/PublicMethods.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/test_support.h"
+
+TEST(CJS_PublicMethods, IsNumber) {
+  // TODO(weili): Check whether results from case 0, 1, 10, 15 are intended.
+  struct {
+    const wchar_t* input;
+    bool expected;
+  } test_data[] = {
+      // Empty string.
+      {L"", true},
+      // Only whitespaces.
+      {L"  ", true},
+      // Content with invalid characters.
+      {L"xyz00", false},
+      {L"1%", false},
+      // Hex string.
+      {L"0x234", false},
+      // Signed numbers.
+      {L"+123", true},
+      {L"-98765", true},
+      // Numbers with whitespaces.
+      {L"  345 ", true},
+      // Float numbers.
+      {L"-1e5", false},
+      {L"-2e", false},
+      {L"e-5", true},
+      {L"0.023", true},
+      {L".356089", true},
+      {L"1e-9", true},
+      {L"-1.23e+23", true},
+      // Numbers with commas.
+      {L"1,000,000", false},
+      {L"560,024", true},
+      // Regular numbers.
+      {L"0", true},
+      {L"0123", true},
+      {L"9876123", true},
+  };
+  for (size_t i = 0; i < FX_ArraySize(test_data); ++i) {
+    EXPECT_EQ(test_data[i].expected,
+              CJS_PublicMethods::IsNumber(test_data[i].input))
+        << "for case " << i;
+  }
+}