Need help, plz

[MarkoMarko]

I need some help.
I want to use javascript to open new window and then use javascript commands on that window. Like change form field value.
I used this code to open a window but i don't know how to do some other commands on that newly opened window

<script>
newwin = window.open( 'link to some site', '', 'status=1,toolbar=1' );
</script>

Thx.