Remove certain string from textbox

[Yourmomsfire]

I want a textbox to actively search for 2 strings to delete them, one being "http://" and the other "https://"
ive tried using a timer as such

   Private Sub Timer1_Tick(sender As Object, e As EventArgs)
        If txtURL.Text = "https://" Then
            txtURL.Text = ""
        End If

        If txtURL.Text = "http://" Then
            txtURL.Text = ""
        End If
    End Sub

and that doesn't work. What else can I do? I want it to get rid of the "http://" or "https://" the second it is typed or pasted into the textbox.
Thanks