I have to click a HTML button programatically which is on the 3rd page of the website. The button is without id. It has just name type and value. The HTML code of the button is given below

<FORM NAME='form1' METHOD='post' action='/dflogin.php'> <INPUT TYPE='hidden' NAME='txtId' value='E712050-15'><INPUT TYPE='hidden' NAME='txtassId' value='1'><INPUT TYPE='hidden' NAME='txtPsw'  value='HH29'><INPUT TYPE='hidden' NAME='txtLog' value='0'><h6 align='right'><INPUT TYPE='SUBMIT' NAME='btnSub' value='Next' style='background-color:#009900; color:#fff;'></h6></FORM>

I am using the following code to click it

Dim i As Integer
Dim allButtons As HtmlElementCollection

allButtons = WebBrowser1.Document.GetElementsByTagName("input")

i = 0
For Each webpageelement As HtmlElement In allButtons
    i += 1
    If i = 5 Then
        webpageelement.InvokeMember("click")
    End If
Next

But I am not able to click it. I am using the vb.net 2008 platform. Can anyone tell me the solution to click it?