asp 截取字符串函数,计算一汉字等于2个英文

'str  要截取的字符串
'strlen 截取字数
'str2 截取字符串后要加的字符。如：...
function gotTopic(str,strlen,str2)
    if str="" or isnull(str) then
        gotTopic=""
        exit function
    end if
   
    dim l,t,c, i
    str=replace(replace(replace(replace(str,"&nbsp;"," "),"&quot;",chr(34)),"&gt;",">"),"&lt;","<")
    l=len(str)
    t=0
   
    for i=1 to l
        c=Abs(Asc(Mid(str,i,1)))
        if c>255 then
            t=t+2
        else
            t=t+1
        end if
       
        if t>cint(strlen) then
          if str2<>"" then i=i-1
            gotTopic=left(str,i-1) & str2
            exit for
        else
            gotTopic=str
        end if
    next
    gotTopic=replace(replace(replace(replace(gotTopic," ","&nbsp;"),chr(34),"&quot;"),">","&gt;"),"<","&lt;")
end function

这个函数可以过滤html来截取哦，就是html与汉字混合的他也可以只截取中文哦。