object not supporting action error

<SCRIPT LANGUAGE="JAVASCRIPT" TYPE="TEXT/JAVASCRIPT">

window.confirm("Please Wait!");

if (screen.width==800||screen.height==600)//if 800x600

window.location("http://www.friendship.co.nr/index.php")

elseif (screen.width==640||screen.height==480)//if 640x480

window.location("http://www.friendship.co.nr/error.php")

elseif (screen.width==1024||screen.height==768)//if 1024x768

window.location("http://www.friendship.co.nr/index2.php")

else//if all else

window.location("http://www.friendship.co.nr/error.php")

</script>

This is my code..

I am getting the error "Error: Object doesn't support this action". what should i do.

[1217 byte] By [pratik29a] at [2007-11-15]