diff --git a/web/viewer.js b/web/viewer.js
index ae047c732..b31378ce8 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -1555,7 +1555,7 @@ var PDFView = {
     var params = {};
     for (var i = 0, ii = parts.length; i < ii; ++i) {
       var param = parts[i].split('=');
-      var key = param[0];
+      var key = param[0].toLowerCase();
       var value = param.length > 1 ? param[1] : null;
       params[decodeURIComponent(key)] = decodeURIComponent(value);
     }