diff --git a/koptilnya/libs/utils.txt b/koptilnya/libs/utils.txt
index eff5fa9..65881a5 100644
--- a/koptilnya/libs/utils.txt
+++ b/koptilnya/libs/utils.txt
@@ -69,7 +69,7 @@ function byteTable(str, start, length)
 end
 
 function isURL(str)
-    local _1, _2, prefix = tx:find("^(%w-):")
+    local _1, _2, prefix = str:find("^(%w-):")
 
-    return prefix == "http" or prefix == "https" or prefix == "data
+    return prefix == "http" or prefix == "https" or prefix == "data"
 end
\ No newline at end of file