diff --git a/core/fxcrt/xml/cfx_xmlinstruction.cpp b/core/fxcrt/xml/cfx_xmlinstruction.cpp
index dabd538..35b68e4 100644
--- a/core/fxcrt/xml/cfx_xmlinstruction.cpp
+++ b/core/fxcrt/xml/cfx_xmlinstruction.cpp
@@ -62,7 +62,7 @@
         AttributeToString(it.first, it.second).AsStringView());
   }
 
-  for (auto target : m_TargetData) {
+  for (const WideString& target : m_TargetData) {
     WideString ws = L" \"";
     ws += target;
     ws += L"\"";
diff --git a/core/fxcrt/xml/cfx_xmlnode.cpp b/core/fxcrt/xml/cfx_xmlnode.cpp
index 1851a4d..5e787ed 100644
--- a/core/fxcrt/xml/cfx_xmlnode.cpp
+++ b/core/fxcrt/xml/cfx_xmlnode.cpp
@@ -110,16 +110,18 @@
 
 void CFX_XMLNode::Save(const RetainPtr<CFX_SeekableStreamProxy>& pXMLStream) {}
 
-WideString CFX_XMLNode::EncodeEntities(WideString value) {
-  value.Replace(L"&", L"&amp;");
-  value.Replace(L"<", L"&lt;");
-  value.Replace(L">", L"&gt;");
-  value.Replace(L"\'", L"&apos;");
-  value.Replace(L"\"", L"&quot;");
-  return value;
+WideString CFX_XMLNode::EncodeEntities(const WideString& value) {
+  WideString ret = value;
+  ret.Replace(L"&", L"&amp;");
+  ret.Replace(L"<", L"&lt;");
+  ret.Replace(L">", L"&gt;");
+  ret.Replace(L"\'", L"&apos;");
+  ret.Replace(L"\"", L"&quot;");
+  return ret;
 }
 
-WideString CFX_XMLNode::AttributeToString(WideString name, WideString value) {
+WideString CFX_XMLNode::AttributeToString(const WideString& name,
+                                          const WideString& value) {
   WideString ret = L" ";
   ret += name;
   ret += L"=\"";
diff --git a/core/fxcrt/xml/cfx_xmlnode.h b/core/fxcrt/xml/cfx_xmlnode.h
index cf2158a..76625e3 100644
--- a/core/fxcrt/xml/cfx_xmlnode.h
+++ b/core/fxcrt/xml/cfx_xmlnode.h
@@ -45,8 +45,8 @@
   void DeleteChildren();
 
  protected:
-  WideString AttributeToString(WideString name, WideString value);
-  WideString EncodeEntities(WideString value);
+  WideString AttributeToString(const WideString& name, const WideString& value);
+  WideString EncodeEntities(const WideString& value);
 
  private:
   CFX_XMLNode* parent_ = nullptr;
diff --git a/fpdfsdk/fsdk_actionhandler.cpp b/fpdfsdk/fsdk_actionhandler.cpp
index c0e413f..305d905 100644
--- a/fpdfsdk/fsdk_actionhandler.cpp
+++ b/fpdfsdk/fsdk_actionhandler.cpp
@@ -525,7 +525,7 @@
 void CPDFSDK_ActionHandler::RunScriptForAction(
     const CPDF_Action& action,
     CPDFSDK_FormFillEnvironment* pFormFillEnv,
-    std::function<void(IJS_EventContext* context)> cb) {
+    const RunScriptCallback& cb) {
   if (!pFormFillEnv->IsJSPlatformPresent())
     return;
 
@@ -536,10 +536,9 @@
   RunScript(pFormFillEnv, swJS, cb);
 }
 
-void CPDFSDK_ActionHandler::RunScript(
-    CPDFSDK_FormFillEnvironment* pFormFillEnv,
-    const WideString& script,
-    std::function<void(IJS_EventContext* context)> cb) {
+void CPDFSDK_ActionHandler::RunScript(CPDFSDK_FormFillEnvironment* pFormFillEnv,
+                                      const WideString& script,
+                                      const RunScriptCallback& cb) {
   IJS_Runtime* pRuntime = pFormFillEnv->GetIJSRuntime();
   IJS_EventContext* pContext = pRuntime->NewEventContext();
 
diff --git a/fpdfsdk/fsdk_actionhandler.h b/fpdfsdk/fsdk_actionhandler.h
index 1aaf2f9..0e5af1a 100644
--- a/fpdfsdk/fsdk_actionhandler.h
+++ b/fpdfsdk/fsdk_actionhandler.h
@@ -57,12 +57,14 @@
                                 PDFSDK_FieldAction* data);
 
  private:
+  using RunScriptCallback = std::function<void(IJS_EventContext* context)>;
+
   void RunScriptForAction(const CPDF_Action& action,
                           CPDFSDK_FormFillEnvironment* pFormFillEnv,
-                          std::function<void(IJS_EventContext* context)> cb);
+                          const RunScriptCallback& cb);
   void RunScript(CPDFSDK_FormFillEnvironment* pFormFillEnv,
                  const WideString& script,
-                 std::function<void(IJS_EventContext* context)> cb);
+                 const RunScriptCallback& cb);
 
   bool ExecuteDocumentOpenAction(const CPDF_Action& action,
                                  CPDFSDK_FormFillEnvironment* pFormFillEnv,