mybb - Javascript: Redirecting to another site through a popup -

i'm quite bad javascript , can't work out solution need to. i'm having website , i'm trying make redirection site, through popup.

example :

<script>alert(this prompt message)</scrip>  <script>window.location="http://this-will-redirect-me-to-another-link.com";</scrip> 

like can see use second javascript redirect persons page, due reasons can't use work half of page(the script kinda 'sandboxed'), if i'd make popup(the first alert script) second script out of 'sandbox'. there has ideas how should implement or can done otherwise php or html?

i'm having mybb forum , there's shoutbox i'm using. there's command change notice of shoutbox , command such /notice new notice | noted new notice can changed javascript , it'll work such /notice js code here | thought if make such javascript redirect people webpage. i'm having such forum it's needed redirect main page one, i'd apply it. staffs in forum well, there's problem. adding

/notice window.location="http://this-will-redirect-me-to-another-link.com"; it'll affect shoutbox , shoutbox being redirected webpage, alert works whole forum thought maybe can redirect them somewhere else alert. want know possible 1 script staffs able it. know it's serious security risk & can otherwise also, i'd experiment it.

i hope can help. :)

try:

  window.open('url other site', 'window name', 'width=900,height=650,scrollbars=yes');