Show warning when attempting to attach more than the allowed number of attachments (#18555).

Patch by Mizuki ISHIKAWA.


git-svn-id: http://svn.redmine.org/redmine/trunk@19620 e93f8b46-1217-0410-a6f0-8f06a7374b81

public/javascripts/attachments.js

@@ -29,6 +29,8 @@ function addFile(inputEl, file, eagerUpload) {
 
     addAttachment.toggle(attachmentsFields.children().length < maxFiles);
     return attachmentId;
+  } else {
+    alert($('input.file_selector').data('max-number-of-files-message'));
   }
   return null;
 }