asp ajax注册验证之 防止用户名输入空格

<%
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function replacetext(fstring,patrn,replstr)
    set regex = new regexp     ' 建立正则表达式。
        regex.pattern = patrn ' 设置模式。
        regex.ignorecase = true ' 设置是否区分大小写。
        regex.global = true ' 设置全局可用性。
        replacetext = regex.replace(""&fstring&"",""&replstr&"") ' 作替换。
    set regex=nothing
end function
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function htmlencode(fstring)
    fstring=trim(fstring)
    fstring=replace(fstring,chr(9),"")
    fstring=replace(fstring,chr(13),"")
    fstring=replace(fstring,chr(22),"")
    fstring=replace(fstring,chr(38),"&")    '“&”
    fstring=replace(fstring,chr(32)," ")    '“ ”
    fstring=replace(fstring,chr(34),""")    '“"”
    fstring=replace(fstring,chr(37),"%")    '“%”
    fstring=replace(fstring,chr(39),"'")    '“'”
    fstring=replace(fstring,chr(42),"*")    '“*”
    fstring=replace(fstring,chr(43),"+")    '“+”
    fstring=replace(fstring,chr(44),",")    '“,”
    fstring=replace(fstring,chr(45)&chr(45),"--")    '“--”
    fstring=replace(fstring,chr(92),"\")    '“”
    'fstring=replace(fstring,chr(95),"_")    '“_”
    fstring=replace(fstring,chr(40),"(")    '“(”
    fstring=replace(fstring,chr(41),")")    '“)”
    fstring=replace(fstring,chr(60),"<")    '“<”
    fstring=replace(fstring,chr(62),">")    '“>”
    fstring=replace(fstring,chr(123),"{")    '“{”
    fstring=replace(fstring,chr(125),"}")    '“}”
    fstring=replace(fstring,chr(59),";")    '“;”
    fstring=replace(fstring,chr(10),"<br>")
    fstring=replacetext(fstring,"([&#])([a-z0-9]*);","$1$2;")
    fstring=replacetext(fstring,"(fuck|shit)",string(len("&$1&"),"*"))
    if issqldatabase=0 then '过滤片假名(日文字符)[u30a0-u30ff] by yuzi
        fstring=escape(fstring)
        fstring=replacetext(fstring,"%u30([a-f][0-f])","0$1;")
        fstring=unescape(fstring)
    end if
    htmlencode=fstring
end function
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function requestint(fstring)
    requestint=request(fstring)
    if isnumeric(requestint) then
        requestint=int(requestint)
    else
        requestint=0
    end if
end function
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username=htmlencode(unescape(request.querystring("username")))
usernamelength=requestint("usernamelength")
if len(username)<>usernamelength then
    response.write "用户名非法！"
else
    response.write "用户名合法！"
end if
%>