Internet Explorer interation

I have an online form that I need to frequently populate from an excel spreadsheet, on the first page is a drop down box where I would normally select a category from. Why I click the category using the mouse it automatically advances me through to the next page, however when I use the macro below to do it, whilst the box shows the correct category, the page is not advanced. Can you help me?

Sub DropDown()

    Dim ie As InternetExplorer

    Set ie = New InternetExplorer
    ie.Visible = True
    ie.Navigate "http://MYSITE/choose_cat.php"

    Do Until ie.ReadyState = READYSTATE_COMPLETE
    Loop

    ie.document.forms(1).Item("catid").Value = "28"
   
End Sub

As a bit of further information this is how the website deals with the box being changed (I don't understand it!):

<select name="catid" onchange="checkSelectedOption(this.value, document.add_ad,'Categories marked with *.');">

Try clicking the Select element or firing its onChange event:

ie.document.forms(1).Item("catid").Click
'Or
ie.document.forms(1).Item("catid").FireEvent "onChange"

You will need an ie.ReadyState wait loop after this.

Get a reference to the link (HTMLAnchorElement). One way is by looping through IE.Document.links, looking for the link with innerText = "Upload Picture", or href containing part of the URL, e.g. "www.mysite.com/upload_file" (use Instr function). Once you have the reference, click it using:

theLink.Click

IE.Document.links, not IE.Document.forms! Try this:

    Dim link As Object
    
    For Each link In IE.document.Links
        If link.innerText = "Upload Picture" Then
            link.Click
            Exit For
        End If
    Next