For Each Item As Object In ListBox1.SelectedItems
                TextBox2.AppendText(Item.ToString + Environment.NewLine)
            Next
            Dim str As String = TextBox2.Text
            Dim leftPart As String = str.Split(":")(0)
            Dim test As String = TextBox2.Text
            Dim phrase As String = test.Substring(test.IndexOf(":"c) + 1)

WebControl1.ExecuteJavascript("document.getElementById('email').value=""" + leftPart + """;")
                Dim leftpar2 As String
                leftpar2 = phrase
                MsgBox(phrase)
                Try
                    WebControl1.ExecuteJavascript("document.getElementById('pass').value=""" + leftpar2 + """;")
                Catch ex As Exception
                    MsgBox(ex.ToString)
                End Try

Dim phrase As String = "test"