利用统计文章字数，然后达到一定字数就截断输出，但是分页的内容就会在莫名其妙的地方截断，不是很友好。
很简单，在要截断的地方附近找下面的符号:
；’”？。！;'".!
如果后面存在<p>或<br>就分页。主要是要研究文章的格式。
<%
if Request.ServerVariables("Content_Length") > 0 then
content = Request.Form("textarea1")

PageLength = 1000                '每页字数
CLength = Len(content)
PageCount = Int(Clength/PageLength) + 1      '计算页数

dim PageArray
redim PageArray(PageCount)

Seperator = Array(chr(13),chr(10),"。","！","？","；","，","”","’")    '分隔符

PageArray(0) = 0
Pos = 0
for j=0 to ubound(Seperator)
Pos = instr(PageArray(i)+900,content,Seperator(j)) 'PageArray(i)+900 附近位置是100字，1-999可调
while Pos > 0 and Pos < (i+1)*PageLength and Pos > i*PageLength
PageArray(i) = Pos
Pos = instr(Pos+PageLength,content,Seperator(j))
wend

if PageArray(i) > 0 then
Response.Write "0:i¦ "&PageArray(i)&"<br>"&j&":j"&Seperator(j)&"<br>"
j = j + ubound(Seperator) + 1
end if
next

for i=1 to PageCount-1
PageArray(i) = 0
Pos = 0
for j=0 to ubound(Seperator)
Pos = instr(PageArray(i-1)+950,content,Seperator(j))
while Pos > 0 and Pos < (i+1)*PageLength and Pos > i*PageLength
PageArray(i) = Pos
Pos = instr(Pos+PageLength,content,Seperator(j))
wend

if PageArray(i) > 0 then
Response.Write i&":i¦ "&PageArray(i)&"<br>"&j&":j"&Seperator(j)&"<br>"
j = j + ubound(Seperator) + 1
end if
next
next

output = mid(content,1,PageArray(0))
output = replace(output,chr(13),"<br>")
Response.Write "<br><br>第1段<br>"
Response.Write output

for i=1 to PageCount-2
output = mid(content,PageArray(i-1)+1,PageArray(i)-PageArray(i-1))
output = replace(output,chr(13),"<br>")
Response.Write "<br><br>第"&i+1&"段<br>"
Response.Write output
next

'最后一段的输出就没写了

else
%>
<FORM action="" method=POST id=form1 name=form1>
<TEXTAREA rows=70 cols=120 id=textarea1 name=textarea1>
</TEXTAREA>
<INPUT type="submit" value="Submit" id=submit1 name=submit1>
</FORM>
<%end if%>