Standard CustomValidator Textbox

Imports System.Web.UI.WebControls
Namespace CustomCtrl
    Public Class CustTextBox
        Inherits TextBox

        Private _ValidateItem As ValidateValue
        Private _IsRequired As Boolean
        Private _ExpressionValue As String

        'Oninit we will set the 
        Protected Overrides Sub OnInit(ByVal e As System.EventArgs)
            Dim strRegExp As String = ""

            Select Case ValidateItem
                Case ValidateValue.Email
                    strRegExp = "^([\\w\\-\\.]+)@((\\[([0-9]{1,3}\\.){3}[0-9]{1,3}\\])|(([\\w\\-]+\\.)+)([a-zA-Z]{2,4}))$"
                Case ValidateValue.URL
                    strRegExp = "http(s)?://([\\w-]+\\.)+[\\w-]+(/[\\w- ./?%&=]*)?"
                Case ValidateValue.PhoneNumber
                    strRegExp = "((\\(\\d{3}\\) ?)|(\\d{3}-))?\\d{3}-\\d{4}"
                Case ValidateValue.CreditCard
                    strRegExp = "^(\\d{4}[- ]){3}\\d{4}|\\d{16}$"
                Case ValidateValue.MonthYear
                    strRegExp = "(((0[123456789]|10|11|12)([/])(([1][9][0-9][0-9])|([2][0-9][0-9][0-9]))))"
                Case ValidateValue.MonthDayYear
                    strRegExp = "^(([1-9])|(0[1-9])|(1[0-2]))\\/(([0-9])|([0-2][0-9])|(3[0-1]))\\/(([0-9][0-9])|([1-2][0,9][0-9][0-9]))$"
                Case ValidateValue.Time
                    strRegExp = "^ *(1[0-2]|[1-9]):[0-5][0-9] *(a|p|A|P)(m|M) *$"
                Case ValidateValue.CustomExpression
                    strRegExp = ExpressionValue

            End Select

            Me.Attributes.Add("onblur", "Check('" + strRegExp + "',this,'" + IsRequired.ToString + "')")
            
            MyBase.OnInit(e)

        End Sub

        Protected Overrides Sub Render(ByVal writer As System.Web.UI.HtmlTextWriter)
            Dim strScript As String = "<script> function Check(regex,obj,reqd) {re = new RegExp(regex); var Prefix=obj.id; var Ctrl=document.getElementById(Prefix);var value=Ctrl.value;  if (reqd=='True'){if (value==''){alert('Value Required');Ctrl.focus();}else{if (re.test(value))  {alert('Valid');}   else { alert('InValid'); Ctrl.focus(); }} }else {if (value==''){}else{if (re.test(value))  {alert('Valid');}    else { alert('InValid'); Ctrl.focus();}}}}</script> "
            writer.WriteLine(strScript)
            MyBase.Render(writer)
        End Sub

        Public Enum ValidateValue
            Email
            PhoneNumber
            URL
            CreditCard
            MonthYear
            MonthDayYear
            Time
            CustomExpression
        End Enum
        Public Property ValidateItem() As ValidateValue
            Get
                Return _ValidateItem
            End Get
            Set(ByVal value As ValidateValue)
                _ValidateItem = value
            End Set
        End Property

        Public Property IsRequired() As Boolean
            Get
                Return _IsRequired
            End Get
            Set(ByVal value As Boolean)
                _IsRequired = value
            End Set
        End Property

        Public Property ExpressionValue() As String
            Get
                Return _ExpressionValue
            End Get
            Set(ByVal value As String)
                _ExpressionValue = value
            End Set
        End Property
    End Class
End Namespace