add check in shelf admin

shelfs/static/js/shelfs_admin.js

@@ -600,6 +600,9 @@ $(document).ready(function() {
             } else if (barcode.length == 12 && barcode.indexOf('0') !== 0) {
             // User may use a scanner which remove leading 0
                 barcode = '0' + barcode;
+            } else if (barcode.length >= 8) {
+                // For EAN8
+                barcode = barcode.substring(barcode.length-8);
             }