diff --git a/src/ESPUI.h b/src/ESPUI.h
index 771b401..76143c4 100644
--- a/src/ESPUI.h
+++ b/src/ESPUI.h
@@ -201,7 +201,8 @@ public:
 
     void updateVisibility(uint16_t id, bool visibility, int clientId = -1);
 
-    // Set optional global custom JavaScript to be included in the UI.
+    // Set optional user-defined JavaScript to be included in the UI.
+    // js: JavaScript code as a C-string. Must remain valid for the lifetime of the ESPUIClass instance.
     void setCustomJS(const char* js);
 
     // Variables