VBScript HTTP-如何读取DOM元素值并让服务器正确答复

Question

I'm having lots of trouble with a VBScript that I'm putting together that, when executed, automatically logs into a webpage. The problem I'm facing at the moment is that my POST doesn't mimic correctly the same as the browser does. Any help is greatly appreciated!

EDIT1: I found a sloppy way to read the DOM element value, but even then there is something wrong with my POST because it differs from that of the browser.

EDIT2: Helen's answer steered me in the right direction, now it works perfectly.

This is the code:

Dim URL
URL = "http://192.168.0.10/login.php"

Dim http : Set http = CreateObject("Msxml2.ServerXMLHTTP.6.0")
http.Open "GET", URL, FALSE
http.Send
Dim html : Set html = CreateObject("HTMLFILE")
html.write http.responseText
' Getting the DOM element's value by it's name
Dim rnd : rnd = html.getElementsByName("rnd").[0].value
'WScript.Echo rnd
sRequest = "username=admin&password=admin&rnd=" & rnd
'Msgbox sRequest, 0, "Final sRequest"
SetCookie = http.getResponseHeader("Set-Cookie")
'Bellow I trim an unnecessary part of the cookie (; path=/;) to keep only the AuthID
SetCookie = Left(SetCookie, Len(SetCookie) - 9)
'Msgbox SetCookie, 0, "Cookie Value"
Set http = nothing

http.Open "POST", URL, False
http.setRequestHeader "Host", "192.168.0.10"
http.setRequestHeader "Content-Length", Len(sRequest)
http.setRequestHeader "Cache-Control", "max-age=0"
http.setRequestHeader "Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8"
http.setRequestHeader "Origin", "http://192.168.0.10"
http.setRequestHeader "User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.137 Safari/537.36"
http.setRequestHeader "Content-Type", "application/x-www-form-urlencoded"
http.setRequestHeader "Referer", "http://192.168.0.10/login.php"
http.setRequestHeader "Accept-Encoding", "gzip,deflate,sdch"
http.setRequestHeader "Accept-Language", "en-US;q=0.6,en;q=0.4"
http.setRequestHeader "Cookie", SetCookie
'Msgbox SetCookie, 0, "Cookie Value"
http.Send sRequest
'Msgbox sRequest, 0, "Final sRequest"
'HTTPGet = http.responseText
Set http = nothing

Thanks again Helen! )

Answer 1

Is this random DOM element on the http://192.168.0.10/login.php page? You could GET the page source and load it into an HTMLFILE object. Then you'll be able to extract the needed element, eg using getElementById :

http.Open "GET", "httpp://192.168.0.10/login.php", False
http.Send

Dim html : Set html = CreateObject("HTMLFILE")
html.write http.responseText

Dim rnd : rnd = html.getElementsByName("rnd").[0].value ' Replace with your element query
WScript.Echo rnd