Pop-up confirmation window makes rollback function can not work for pages named in Chinese

When click rollback in history page to rollback a page, the system will pop up a window to confirm whether the user is sure to rollback. But for a page named in Chinese, it can not rollback because of some encoding problem.
The problem must be caused by the pop-up window, because when I enable the pop-up window, the rollback can work for a page named in Chinese.
See 'historyinline.vm'
$a href=tdoc.getURL("deleteversions","rev=$version$lang")" onclick="if (confirm('$msg.get("core.versions.delete.confirm.single", [$version])'))

return false;"
I changed it to:
a href="$tdoc.getURL("rollback","rev=$version$lang")"
then rollback can work