2 files changed, 3 insertions, 3 deletions
diff --git a/fpdfsdk/src/javascript/PublicMethods.cpp b/fpdfsdk/src/javascript/PublicMethods.cpp
index 13239aeb1d..e898214cd8 100644
--- a/fpdfsdk/src/javascript/PublicMethods.cpp
+++ b/fpdfsdk/src/javascript/PublicMethods.cpp
@@ -116,7 +116,7 @@ FX_BOOL CJS_PublicMethods::IsDigit(wchar_t ch) {
 }
 
 FX_BOOL CJS_PublicMethods::IsDigit(char ch) {
-  return std::isdigit(ch);
+  return (ch >= '0' && ch <= '9');
 }
 
 FX_BOOL CJS_PublicMethods::IsAlphabetic(wchar_t ch) {
diff --git a/fpdfsdk/src/javascript/util.cpp b/fpdfsdk/src/javascript/util.cpp
index cf10bbd7b4..14e15c1b6f 100644
--- a/fpdfsdk/src/javascript/util.cpp
+++ b/fpdfsdk/src/javascript/util.cpp
@@ -425,7 +425,7 @@ void util::printx(const std::string& cFormat,
         break;
       case 'X': {
         while (itSource < iSize) {
-          if (std::isdigit(cSource[itSource]) ||
+          if ((cSource[itSource] >= '0' && cSource[itSource] <= '9') ||
               (cSource[itSource] >= 'a' && cSource[itSource] <= 'z') ||
               (cSource[itSource] >= 'A' && cSource[itSource] <= 'Z')) {
             cPurpose += cSource[itSource];
@@ -450,7 +450,7 @@ void util::printx(const std::string& cFormat,
       } break;
       case '9': {
         while (itSource < iSize) {
-          if (std::isdigit(cSource[itSource])) {
+          if (cSource[itSource] >= '0' && cSource[itSource] <= '9') {
             cPurpose += cSource[itSource];
             itSource++;
             break;