Unable to to locate and click a submit button using mshtml.HTMLInputElement - vb.net

Question

Below is is an HTML form and below that, is a vb procedure, "LoginExamp" that enters in the username and password. I am unable to locate the button however and click it since it does not seem to show up as a mshtml.HTMLInputElement. "htmlInput.click()" never runs. How can I adjust the loginExamp code so that the button is clicked. Thanks for any help.
<form id="loginform" name="loginform" method="post" action="">
<input id="username" class="formfield" type="text" value="User Name" maxlength="40" name="Xusername">
<input id="password" class="formfield" type="password" onfocus="clearDefault(this)" maxlength="40" name="Xpassword">
<button class="subButton" onclick="javascript: submitform()">submit!</button>
</form>
With the below code
Public Sub loginExamp()
Dim objIE As SHDocVw.InternetExplorer
Dim htmlDoc As mshtml.HTMLDocument
Dim htmlInput As mshtml.HTMLInputElement
Dim htmlColl As mshtml.IHTMLElementCollection
Dim url As Object
url = "http://localhost/ButtonClickTest.html" 'just a test page with the loginform above
objIE = New SHDocVw.InternetExplorer
With objIE
.Navigate(url)
.Visible = True
While .Busy = True
Threading.Thread.Sleep(2000)
End While
htmlDoc = .Document
htmlColl = htmlDoc.getElementsByTagName("INPUT")
While .Busy = True
Threading.Thread.Sleep(2000)
End While
For Each htmlInput In htmlColl
If htmlInput.name = "Xusername" Then
htmlInput.value = "theusername" 'this works
ElseIf htmlInput.name = "Xpassword" Then
htmlInput.value = "thepassword" 'This works too
End If
If htmlInput.className = "subButton" Then 'This is never true
htmlInput.click() 'This line never runs
End If
Next htmlInput
End With
End Sub

Answer 1

I was able to finally figure out the answer to my own question. Below is the code that works. Both the username and password is entered and also the button is clicked.
Public Sub loginExamp()
Dim objIE As SHDocVw.InternetExplorer
Dim htmlDoc As mshtml.HTMLDocument
Dim htmlInput As Object
Dim url As String
url = "http://localhost/N1/ButtonClickTest.html"'test page with the loginform above
objIE = New SHDocVw.InternetExplorer
With objIE
.Navigate(url)
.Visible = True
While .Busy = True
Threading.Thread.Sleep(2000)
End While
htmlDoc = .Document
Dim htmlColl As mshtml.HTMLFormElement = DirectCast(htmlDoc.forms.item("loginform"), mshtml.HTMLFormElement)
While .Busy = True
Threading.Thread.Sleep(2000)
End While
For Each htmlInput In htmlColl
If htmlInput.name = "Xusername" Then
htmlInput.value = "theusername"
ElseIf htmlInput.name = "Xpassword" Then
htmlInput.value = "thepassword"
End If
If htmlInput.className = "subButton" Then
htmlInput.click()
End If
Next htmlInput
End With
End Sub