diff --git a/index.html b/index.html
index dffa80b..aad308e 100644
--- a/index.html
+++ b/index.html
@@ -284,6 +284,7 @@
 		</div>
 
 		<!-- Base Libs -->
+		<script src="js/error.js" type="text/javascript"></script>
 		<script src="js/util.js" type="text/javascript"></script>
 		<script src="js/input.js" type="text/javascript"></script>
 		<script src="js/commands.js" type="text/javascript"></script>
diff --git a/js/error.js b/js/error.js
new file mode 100644
index 0000000..3c1e61d
--- /dev/null
+++ b/js/error.js
@@ -0,0 +1,7 @@
+/**
+ * This is a file to configure custom errors
+ */
+
+/* Proxy Restriction Errors */
+class ProxyReadOnlySetError extends Error {}
+class ProxyWriteOnceSetError extends Error {}