谁能帮我解释一下这个函数的每一个词的意思
function changechr(str)
changechr=replace(replace(replace(replace(str,"<","<"),">",">"),chr(13),"<br>")," "," ")
changechr=replace(replace(replace(replace(changechr,"[starark]","<img src="),"","<b>"),"[red]","<font color=CC0000>"),"[big]","<font size=7>")
changechr=replace(replace(replace(replace(changechr,"[/starark]","></img>"),"","</b>"),"[/red]","</font>"),"[/big]","</font>")
end function