Enable/Disable RequiredFieldValidator with Javascript

Sometimes you may need to enable/disable validators on client side. you can easily do this using ValidatorEnable function in the Asp.net javacsript Script Library. Here is an example:

<script language="javascript" type="text/javascript">
    function EnableDisableVote() {
        var radio = document.getElementById('<%= rdoYesNo.ClientID %>');
        var radioArray = radio.getElementsByTagName("input");
        var isChecked = false;
        for (var i = 0; i < radioArray.length; i++) {
            var item = radioArray[i];
            if (item.type == "radio" && item.checked) {
                isChecked = true;
                if (i > 0) {
                    document.getElementById('<%= TextBoxCaseNotes.ClientID %>').disabled = false;
                    ValidatorEnable(document.getElementById('<%= RequiredFieldValidatorCasseNotes.ClientID %>'), true);
                }
                else {
                    document.getElementById('<%= TextBoxCaseNotes.ClientID %>').value = '';
                    document.getElementById('<%= TextBoxCaseNotes.ClientID %>').disabled = true;
                    ValidatorEnable(document.getElementById('<%= RequiredFieldValidatorCasseNotes.ClientID %>'), false);
                }
                break;
            }
        }
        if (isChecked && document.getElementById('<%= ChkIagree.ClientID %>').checked) {
            document.getElementById('<%= ButtonVote.ClientID %>').disabled = false;
        }
        else
            document.getElementById('<%= ButtonVote.ClientID %>').disabled = true;
    }
</script>