diff --git a/src/root/static/js/common.js b/src/root/static/js/common.js
index 8296cadb..1fe2f778 100644
--- a/src/root/static/js/common.js
+++ b/src/root/static/js/common.js
@@ -121,7 +121,7 @@ function escapeHTML(s) {
 };
 
 function requestFile(args) {
-    if (!"error" in args) {
+    if (!("error" in args)) {
         args.error = function(data) {
             json = {};
             try {