Option Explicit

Private Type myRECT
    Left As Long
    Top As Long
    Right As Long
    Bottom As Long
End Type

Private Enum CoordType
    Absolute
    Pixels
End Enum

' User32 API functions used to determine screen resolution
Declare Function GetDesktopWindow Lib "User32" () As Long
Declare Function GetWindowRect Lib "User32" (ByVal hWnd As Long, rectangle As myRECT) As Long

' User32 API Mouse functions
Private Declare Sub mouse_event Lib "User32" (ByVal dwFlags As Long, ByVal dx As Long, ByVal dy As Long, ByVal cButtons As Long, ByVal dwExtraInfo As Long)

' Mouse Event Flags
Const MOUSEEVENTF_LEFTDOWN = &H2
Const MOUSEEVENTF_LEFTUP = &H4
Const MOUSEEVENTF_MOVE = &H1
Const MOUSEEVENTF_ABSOLUTE = &H8000

Sub Test()

Dim IExp As SHDocVw.InternetExplorer

Dim hDoc As MSHTML.HTMLDocument
Dim hCol As MSHTML.IHTMLElementCollection
Dim hInp As MSHTML.HTMLInputElement
Dim hPoint As MSHTML.tagPOINT

    Set IExp = New SHDocVw.InternetExplorer
    IExp.Visible = True
    IExp.navigate "http://www.google.co.uk"
    
    Do Until IExp.Busy = False
        DoEvents
    Loop
    
    Set hDoc = IExp.document
    
    ' Find the "search for" input box on the page
    Set hCol = hDoc.getElementsByTagName("input")
    For Each hInp In hCol
        
        If hInp.Name = "q" Then
            hInp.Value = "Test" ' Put in something to look for
            Exit For
        End If
        
    Next hInp
    
    ' Find the search button on the page
    Set hCol = hDoc.getElementsByTagName("input")
    For Each hInp In hCol
          
        If hInp.DefaultValue = "Google Search" Then
            
            ' Scroll IE to top left hand corner
            hDoc.parentWindow.scroll 0, 0
            
            ' Get coordinate of button
            hPoint = GetCoord(hDoc, hInp, Absolute)
            
            ' Move mouse
            mouse_event MOUSEEVENTF_ABSOLUTE + MOUSEEVENTF_MOVE, hPoint.X, hPoint.Y, 0, 0
            
            ' Simulate click
            mouse_event MOUSEEVENTF_LEFTDOWN, 0, 0, 0, 0
            mouse_event MOUSEEVENTF_LEFTUP, 0, 0, 0, 0
            
            Exit For
            
        End If
        
    Next hInp
    

End Sub

Private Function GetCoord(hDoc As MSHTML.HTMLDocument, hEle As MSHTML.HTMLInputElement, Output As CoordType) As MSHTML.tagPOINT

Dim ScreenRes As MSHTML.tagPOINT
Dim hIRectEle As MSHTML.IHTMLRect
Dim Point As MSHTML.tagPOINT
    
    ' Get the screen resolution
    ScreenRes = GetScreenResolution
    
    Set hIRectEle = hEle.getBoundingClientRect
    
    ' Find middle of input element
    Point.X = (hIRectEle.Left + hIRectEle.Right) / 2
    Point.Y = (hIRectEle.Top + hIRectEle.Bottom) / 2
    
    ' Add in offset for where the internet explorer window is located on screen
    Point.X = Point.X + hDoc.parentWindow.screenLeft
    Point.Y = Point.Y + hDoc.parentWindow.screenTop
    
    ' Convert to absolute coords, if necessary
    If Output = Absolute Then
        Point.X = (Point.X / ScreenRes.X) * 65000
        Point.Y = (Point.Y / ScreenRes.Y) * 65000
    End If
    
    GetCoord = Point

End Function

Function GetScreenResolution() As MSHTML.tagPOINT

Dim R As myRECT
Dim hWnd As Long
Dim RetVal As Long
    
    ' Win API calls
    hWnd = GetDesktopWindow()
    RetVal = GetWindowRect(hWnd, R)
    
    GetScreenResolution.X = (R.Right - R.Left)
    GetScreenResolution.Y = (R.Bottom - R.Top)
    
End Function