uBB函数，解释一下这三个函数分别实现的是什么功能，怎样用，详细点，答完给分，不甚感激。
function ubb(content) ubb=content
nowtime=now()
UBB=Convert(ubb,"code")
UBB=Convert(ubb,"html")
UBB=Convert(ubb,"url")
UBB=Convert(ubb,"color")
UBB=Convert(ubb,"font")
UBB=Convert(ubb,"size")
UBB=Convert(ubb,"quote")
UBB=Convert(ubb,"email")
UBB=Convert(ubb,"img")
UBB=Convert(ubb,"swf")
ubb=convert(ubb,"cen")
ubb=convert(ubb,"rig")
ubb=convert(ubb,"lef")
ubb=convert(ubb,"center")
UBB=AutoURL(ubb)
ubb=replace(ubb,"","<b>",1,-1,1)
ubb=replace(ubb,"","</b>",1,-1,1)
ubb=replace(ubb,"","<i>",1,-1,1)
ubb=replace(ubb,"","</i>",1,-1,1)
ubb=replace(ubb,"","<u>",1,-1,1)
ubb=replace(ubb,"","</u>",1,-1,1)
ubb=replace(ubb,"[blue]","<font color='#000099'>",1,-1,1)
ubb=replace(ubb,"[/blue]","</font>",1,-1,1)
ubb=replace(ubb,"[red]","<font color='#990000'>",1,-1,1)
ubb=replace(ubb,"[/red]","</font>",1,-1,1)
for i=1 to 28
ubb=replace(ubb,"{:em"&i&"}","<IMG SRC=emot/emotface/em"&i&".gif ></img>",1,6,1)
ubb=replace(ubb,"{:em"&i&"}","",1,-1,1)
next
ubb=replace(ubb,"["&chr(176),"[",1,-1,1)
ubb=replace(ubb,chr(176)&"]","]",1,-1,1)
ubb=replace(ubb,"/"&chr(176),"/",1,-1,1)
'ubb=replace(ubb,"{;em","{:em",1,-1,1)
end function
function Convert(ubb,CovT) cText=ubb
startubb=1
do while Covt="url" or Covt="color" or Covt="font" or Covt="size"
startubb=instr(startubb,cText,"["&CovT&"=",1)
if startubb=0 then exit do
endubb=instr(startubb,cText,"]",1)
if endubb=0 then exit do
Lcovt=Covt
startubb=startubb+len(lCovT)+2
text=mid(cText,startubb,endubb-startubb)
codetext=replace(text,"[","["&chr(176),1,-1,1)
codetext=replace(codetext,"]",chr(176)&"]",1,-1,1)
'codetext=replace(codetext,"{:em","{;em",1,-1,1)
codetext=replace(codetext,"/","/"&chr(176),1,-1,1)
select case CovT
case "color"
cText=replace(cText,"[color="&text&"]","<font color='"&text&"'>",1,1,1)
cText=replace(cText,"[/color]","</font>",1,1,1)
case "font"
cText=replace(cText,"[font="&text&"]","<font face='"&text&"'>",1,1,1)
cText=replace(cText,"[/font]","</font>",1,1,1)
case "size"
if IsNumeric(text) then
if text>6 then text=6
if text<1 then text=1
cText=replace(cText,"[size="&text&"]","<font size='"&text&"'>",1,1,1)
cText=replace(cText,"[/size]","</font>",1,1,1)