ASP判断文件地址是否有效!

<%
'原创作者:小艺 QQ:52093 时间:2005.6.30
Response.Write("<head><style><!--span{ font-size: 9pt }--></style></head>")
On Error Resume Next
Dim thisurl,thistext
thisurl=Request("thisurl")            '定义文件地址(非Html格式文档)!
if thisurl="" then
     Response.Write("<span>请先输入文件地址!</span>")
     Response.End
End if

Function objxmlhttp(xmlurl)
     On Error Resume Next
     Set objxml = CreateObject("Microsoft.XMLHTTP")
     objxml.Open "get",xmlurl,false
     objxml.setrequestheader "content-type","application/x-www-form-urlencoded"
     objxml.send
     objxmlhttp = objxml.responsebody
     if Err then
           Err.Clear
           Response.Write("<span>建立连接失败,文件不存在或网络有问题!;错误原因:"&Err.Description&"！</span>")
           Response.End
     End if
End Function

Function bytes2BSTR(vIn)
     strReturn = ""
     For i = 1 To LenB(vIn)
           ThisCharCode = AscB(MidB(vIn,i,1))
           If ThisCharCode < &H80 Then
                 strReturn = strReturn & Chr(ThisCharCode)
           Else
                 NextCharCode = AscB(MidB(vIn,i+1,1))
                 strReturn = strReturn & Chr(CLng(ThisCharCode) * &H100 + CInt(NextCharCode))
           i = i + 1
           End If
     Next
     bytes2BSTR = strReturn
End Function

thisurl2=Split(thisurl,",")
For Each ii In thisurl2
     thistext=bytes2BSTR(objxmlhttp(ii))
     if InStr(thistext,"<html>")<>0 then
           Response.Write("<span>"& ii &" <b>×</b></span><br>")
     Else
           Response.Write("<span>"& ii &" <b>√</b></span><br>")
     End if
Next

if Err then
     Err.Clear
     Response.Write("<span>碰到意外!;错误原因:"&Err.Description&"！</span>")
     Response.End
End if
%>