VBA Code Modification

Hello there,
I have some code - originally kindly given to me from someone here a long time ago.
I need to modify it, I am not very good with VB and have been trying last 2 days without success.

Currently this code searches for text which begins with a < and ends with >

I know it is easy to adjust a single start and end character but I wish to search for more - e.g.. start with <span & ends with span>
I really cannot figure this out if I enter these parameters I get no response back, any help gratefully received.
Thanks

EXISTING CODE

Function TrimCell(rng As Range)
    Dim strTemp As String
    Dim n As Long
    Dim switch As Boolean
    
    For n = 1 To Len(rng)
        If Not switch Then
            If Mid(rng, n, 1) = "<" Then
                strTemp = strTemp & Mid(rng, n, 1)
                switch = True
            Else
                strTemp = strTemp & ""
            End If
        Else
            If Mid(rng, n, 1) = ">" Then
                strTemp = strTemp & Mid(rng, n, 1)
                switch = False
            Else
                strTemp = strTemp & Mid(rng, n, 1)
            End If
        End If
    Next
          
    TrimCell = strTemp
End Function

NEW CODE

Function TrimCell(rng As Range)
    Dim strTemp As String
    Dim n As Long
    Dim switch As Boolean
    
    For n = 1 To Len(rng)
        If Not switch Then
            If Mid(rng, n, 1) = "<span" Then
                strTemp = strTemp & Mid(rng, n, 1)
                switch = True
            Else
                strTemp = strTemp & ""
            End If
        Else
            If Mid(rng, n, 1) = "span>" Then
                strTemp = strTemp & Mid(rng, n, 1)
                switch = False
            Else
                strTemp = strTemp & Mid(rng, n, 1)
            End If
        End If
    Next
          
    TrimCell = strTemp
End Function