captcha

Private Sub btn_captcha_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_captcha.Click

        Dim htmlDocument As HtmlDocument = WebBrowser1.Document
        Dim htmlElementCollection As HtmlElementCollection = htmlDocument.Images

        For Each htmlElement As HtmlElement In htmlElementCollection

            Dim imgUrl As String = htmlElement.GetAttribute("src")
            If imgUrl.StartsWith("https://zeus.sii.cl/cvc_cgi/stc/CViewCaptcha.cgi?oper=1&txtCaptcha=") Then
                image_url = imgUrl
                picture_box.ShowDialog()
                Exit For
            End If
            Dim pause As String = ""
        Next

    End Sub