diff --git a/_web_server/server/playground-server.scm b/_web_server/server/playground-server.scm
index 2fe175a..9281116 100755
--- a/_web_server/server/playground-server.scm
+++ b/_web_server/server/playground-server.scm
@@ -910,7 +910,8 @@
 
                 (let ((canvas-width
                        (let ((v (assoc "width" query)))
-                         (and v (string->number (cadr v)) DEFAULT-CANVAS-WIDTH))))
+                         (or (and v (string->number (cadr v)))
+                             DEFAULT-CANVAS-WIDTH))))
                   (make-response
                    (make-log-html log vcd canvas-width)
                    #:content-type 'text/plain)))))