target="main" inside onclick event

i have this script:

<input type="button" value="JRgames" onClick="window.location='http://www.jrgames.net'">

but i want that to open it my "main" frame. (target="main")

please could anyone help?

<input type="button" value="JRgames" onClick="top.frames['main'].location.href='http://www.jrgames.net';">dumpfi

thank you very much,
but how do u make it refresh in the main frame?

i am makin a website that is viewed in a browser with no buttons.
http://www.jrgames.net/index2.htm