Selecting an option in DOM(HTML, Javascript)

That just needs an observation of the webpage, a beginner level demonstration as a starter :

PHP Code: 

Sub Demo1()
             Dim oElt As Object
    With CreateObject("InternetExplorer.Application")
                .Navigate "https://www.oslobors.no/ob_eng/markedsaktivitet/#/details/STL.OSE/overview"
                .Visible = True
          While .Busy Or .ReadyState < 4:  DoEvents:  Wend
          Do: Loop Until .Document.getElementsByTagName("SELECT").Length
        For Each oElt In .Document.getElementsByTagName("SELECT")
              If oElt.Options.Value = "INTRADAY" Then
                 oElt.selectedIndex = 1
             Set oElt = Nothing
                 Exit For
             End If
        Next
    End With
End Sub 


Do you like it ? So thanks to click on bottom left star icon « ★ Add Reputation » !

It only changes what is shown in the 'select' tag/element, it does not change the URL in the button, or the time frame in the chart.

Working on my side :

PHP Code: 

Sub Demo2()
             Dim oElt As Object
    With CreateObject("InternetExplorer.Application")
                .Navigate "https://www.oslobors.no/ob_eng/markedsaktivitet/#/details/STL.OSE/overview"
                .Visible = True
          While .Busy Or .ReadyState < 4:  DoEvents:  Wend
          Do: Loop Until .Document.getElementsByTagName("SELECT").Length
        For Each oElt In .Document.getElementsByTagName("SELECT")
              If oElt.Options.Value = "INTRADAY" Then
                 oElt.Focus
                 CreateObject("WScript.Shell").SendKeys "{DOWN}"
             Set oElt = Nothing
                 Exit For
             End If
        Next
    End With
End Sub 


Do you like it ? So thanks to click on bottom left star icon « ★ Add Reputation » !

That's with a key, not DOM.

First one was via DOM but as you seems so smart, just run the JScript event procedure associated
as you can observe using the webbrowser inner inspector tool …

What does this mean 'just run the JScript event procedure associated
as you can observe using the webbrowser inner inspector tool …'?

What should I inspect?
ob.png
Sending keys requires that the browser is open and is the active window.

I want this to select an option other than 'Intraday' here, so that the URL in the 'Download' button starts with 'https://www.oslobors.no/ob/servlets/excel?type=history&columns=DATE', and not 'https://www.oslobors.no/ob/servlets/excel?type=history&columns=TIME'.

What 'inner help'?
Where on 'MSDN'?

As sending keys works !

In your webbrowser exist help (so an inner one) and an inspector tool which can be called
via right click (like inspect element, depends on the version) or via the F12 key …

On recent webbrowsers you can directly inspect the JScript events linked to an element.

Apply a classic tags web search like MSDN + other words like developer tools.
All Microsoft help is on MSDN whatever Office, VBA, IE, VBScript, Windows, …

Sending keys is not the DOM.

The screenshot is of the 'inspector tool'.

I have searched, read MSDN/forums etc. Question is what exactly should I read, is it possible to change the URL via DOM?

You can't change the URL as it is a JScript event which updates the webpage if I'm not wrong …
So outside DOM so the easy VBA way is to send keys if piloting IE is necessary or to find & execute the JScript event
or to leave VBA for a better Web language …

It's done like this, but I strongly discourage this approach:

Option Explicit

Sub ickyDropdown()

    Dim ie As Object
    Dim obj As Object
    Dim inp As Object
    
    Set ie = CreateObject("InternetExplorer.Application")
    ie.Navigate "https://www.oslobors.no/ob_eng/markedsaktivitet/#/details/STL.OSE/overview"     
    ie.Visible = True
    
    Do
        DoEvents
        On Error Resume Next
            Set obj = ie.Document.all("highcharts-4")
        On Error GoTo 0
    Loop Until Not obj Is Nothing

    'ie has now finished loading
    

    
    Set obj = ie.Document.createEvent("HTMLEvents")
    obj.initEvent "change", False, True
    
    For Each inp In ie.Document.getElementsByTagName("SELECT")
          If inp.Options.Value = "INTRADAY" Then
             inp.selectedIndex = 1
             inp.dispatchevent obj
         Set inp = Nothing
             Exit For
         End If
    Next


End Sub

Because automating ie is very, very slow. It's also much more fragile than the proper approach

Doing it manually is even slower!

'proper approach'?