求助 一小段vbs代码

public n,num,ref
n=0
num="1"
ref=1

sub init
on error resume next

parent.window.focus
setinterval "receive",15000
setinterval "flesh",150000
setinterval "if ref=0 then flesh",1200000
if "guest"="guest" then window.open "welcome.asp","","toolbar=no,width=340,height=200"
end sub

sub receive
on error resume next
if document.forms(0).reftm.value="1" then
document.forms(0).refmenu.value="0"
n=n+1
parent.app13_ft1.window.location="reflesh.asp?n="&n
end if
end sub

sub flesh
on error resume next
if num<>document.forms(0).online_num.value and document.forms(0).refmenu.value="1" then
ref=1
num=document.forms(0).online_num.value
if document.agent.document.forms(0).msgnum.value="0" then document.agent.window.location.reload
if document.friend.document.forms(0).msgnum.value="0" then document.friend.window.location.reload
if document.ollist.document.forms(0).msgnum.value="0" then
document.forms(0).reftm.value="0"
document.ollist.window.location.reload
end if
else
ref=0
end if
end sub

setinterval 是什么意思，搜索也没有