don't parse blank ISBNs

diff --git a/includes/Parser.php b/includes/Parser.php
index f15b4e3..be98d71 100644 (file)
--- a/includes/Parser.php
+++ b/includes/Parser.php
@@ -2094,6 +2094,7 @@ class Parser
                $valid = '0123456789-ABCDEFGHIJKLMNOPQRSTUVWXYZ';
 
                foreach ( $a as $x ) {
+                       if ( $x == '' ) continue;
                        $isbn = $blank = '' ;
                        while ( ' ' == $x{0} ) {
                                $blank .= ' ';