diff --git a/guacamole/src/main/webapp/client.xhtml b/guacamole/src/main/webapp/client.xhtml
index cafd9a8ac..3c4bfb5b0 100644
--- a/guacamole/src/main/webapp/client.xhtml
+++ b/guacamole/src/main/webapp/client.xhtml
@@ -164,12 +164,12 @@
 
                         // Add audio mimetypes to connect_string
                         GuacamoleUI.supportedAudio.forEach(function(mimetype) {
-                            connect_string += "&audio=" + mimetype;
+                            connect_string += "&audio=" + encodeURIComponent(mimetype);
                         });
 
                         // Add video mimetypes to connect_string
                         GuacamoleUI.supportedVideo.forEach(function(mimetype) {
-                            connect_string += "&video=" + mimetype;
+                            connect_string += "&video=" + encodeURIComponent(mimetype);
                         });
 
                         guac.connect(connect_string);