//function to display a confirmation box and return the selected value.
    function confirmBox(strMessage)
    {
        var boolAgree=confirm(strMessage);
        if (boolAgree) return true ;
        else return false ;
    }

    //function to update specified select box with specified values.
    function swapOptions(objSelect, strTextArrayName,strValueArrayName)
    {
        var arrText = eval(strTextArrayName);
        var arrValues = eval(strValueArrayName);
        setOptionText(objSelect,arrText);
        setOptionValues(objSelect,arrValues);
        //objSelect.options[1].selected = true;
        for (c=0; c<arrText.length; c++)
        {
            if (objSelect.options[c].text == "")
            {
                objSelect.options[c].selected = true;
            }
        }
    }

    //function to set select box option text.
    function setOptionText(objSelectBox,arrText)
    {
        objSelectBox.length=arrText.length;
        for (c=0; c<arrText.length; c++)
        {
            objSelectBox.options[c].text=arrText[c];
        }
    }

    //function to set select box option value.
    function setOptionValues(objSelectBox,arrValues)
    {
        objSelectBox.length=arrValues.length;
        for (c=0; c<arrValues.length; c++)
        {
            objSelectBox.options[c].value=arrValues[c];
        }
    }

    //open new window.
    function NewWindow(strWidth, strHeight, strUrl)
    {
        var winl = (screen.width - strWidth) / 2;
        var wint = (screen.height - strHeight) / 2;
        winprops = 'height='+strHeight+',width='+strWidth+',top='+wint+',left='+winl+',scrollbars=yes,resizable'
        win = window.open(strUrl, 'newwindow', winprops)
        if (parseInt(navigator.appVersion) >= 4) { win.window.focus(); }
    }

    function remote(URL, WIDTH, HEIGHT)
    {
        RemoteWin=window.open(URL,WIDTH+HEIGHT,"resizable=yes,toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=auto,copyhistory=0,width=" + WIDTH + ",height=" + HEIGHT + "");
    }

    //function to check the validity of a domain name (excluding the domain suffix).
    function checkDomainPrefix(strDomain)
    {
        var strValidChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-";
        var strDomainName = new String(escape(strDomain));
        var intIndex = 0;
        var boolValid = true;
        var boolInvalidChars = false;
        var boolInvalidHyphen = false;

        //Check length of domain name.
        if (strDomainName.length < 3) {
            alert("The specified domain name is too short.");
            boolValid = false;
        }
        if (strDomainName.length > 64) {
            alert("The specified domain name is too long.");
            boolValid = false;
        }

        //Check characters of domain name.
        for (intIndex = 0; intIndex < strDomainName.length; intIndex++) {
            if (strValidChars.search(strDomainName.charAt(intIndex)) == -1) {
                boolInvalidChars = true;
                boolValid = false;
            }
            else if(strDomainName.charAt(intIndex) == "-") {
                if (intIndex == 0 || intIndex == strDomainName.length - 1) {
                    boolInvalidHyphen = true;
                    boolValid = false;
                }
            }
        }
        if(boolInvalidChars == true) { alert("The domain name must be made up of letters, numbers and hyphens."); }
        if(boolInvalidHyphen == true) { alert("The domain name may not begin or end with a hyphen (-)."); }

        return boolValid;
    }

    //function to check that a domain suffix has been chosen.
    function checkDomainSuffix(objSuffixSelectBox)
    {
        var boolSelected = true;

        if(checkSelectBox(objSuffixSelectBox)==false) {
            alert("A domain suffix must be chosen from the dropdown list.");
            boolSelected = false;
        }

        return boolSelected;
    }

    //function to check contact details.
    function checkContactDetails(objSalutation, strFirstName, strSurName, strCompanyName, objCompanyType, strBuildingName, strBuildingNumber, strStreet, strTown, objCounty, strPostcode, objCountry, strTelephone, strFax, strEmail)
    {
        var boolValid = true;
        var strValidChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 ";
        var strValidNumbers = "0123456789-";
        var strValidTelNumbers = "0123456789 ";
        var strValidEmailChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-.@_";
        var intIndex;
        var boolInvalidChars;
        var boolInvalidHyphen;
        var boolInvalidSpace;
        var strMessage = "";
        var arrEmail;

        //Check salutation.
        if(checkSelectBox(objSalutation)==false) {
            strMessage = strMessage + "A salutation (e.g. 'Mr') must be chosen from the dropdown list.\n";
            boolValid = false;
        }

        //Check first name.
        if(strFirstName.length < 1) {
            strMessage = strMessage + "Your first name or initial must be entered in order to continue.\n";
            boolValid = false;
        }

        //Check surname.
        if(strSurName.length < 2) {
            strMessage = strMessage + "Your surname must be entered in order to continue.\n";
            boolValid = false;
        }

        //Check company name and type.
        if(strCompanyName.length > 0 && checkSelectBox(objCompanyType) == false) {
            strMessage = strMessage + "You must select the correct value from the type of company dropdown list.\n";
            boolValid = false;
        }

        //Check building name and number
        if(strBuildingName.length < 3 && strBuildingNumber.length < 1) {
            strMessage = strMessage + "Your building name or number must be entered in order to continue.\n";
            boolValid = false;
        }

        //Check building number validity.
        if(strBuildingNumber.length > 0) {
            //Check characters of number.
            for (intIndex = 0; intIndex < strBuildingNumber.length; intIndex++) {
                if (strValidNumbers.search(strBuildingNumber.charAt(intIndex)) == -1) {
                    boolInvalidChars = true;
                    boolValid = false;
                }
                else if(strBuildingNumber.charAt(intIndex) == "-") {
                    if (intIndex == 0 || intIndex == strBuildingNumber.length - 1) {
                        boolInvalidHyphen = true;
                        boolValid = false;
                    }
                }
            }
            if(boolInvalidChars == true) { strMessage = strMessage + "Your building number can only be made up of numbers and a hyphen.\n"; boolInvalidChars = false; }
            if(boolInvalidHyphen == true) { strMessage = strMessage + "Your building number may not begin or end with a hyphen (-).\n"; }
        }

        //Check street.
        if(strStreet.length < 3) {
            strMessage = strMessage + "Your street name must be entered in order to continue.\n";
            boolValid = false;
        }

        //Check town.
        if(strTown.length < 3) {
            strMessage = strMessage + "Your town or city must be entered in order to continue.\n";
            boolValid = false;
        }

        //Check county.
        if(checkSelectBox(objCounty) == false) {
            strMessage = strMessage + "You must select your county from the dropdown list.\n";
            boolValid = false;
        }

        //Check postcode.
        if(strPostcode.length < 3) {
            strMessage = strMessage + "Your postcode or zipcode must be entered in order to continue.\n";
            boolValid = false;
        }
        else {
            //Check characters of postcode.
            for (intIndex = 0; intIndex < strPostcode.length; intIndex++) {
                if (strValidChars.search(strPostcode.charAt(intIndex)) == -1) {
                    boolInvalidChars = true;
                    boolValid = false;
                }
                else if(strPostcode.charAt(intIndex) == " ") {
                    if (intIndex == 0 || intIndex == strPostcode.length - 1) {
                        boolInvalidSpace = true;
                        boolValid = false;
                    }
                }
            }
            if(boolInvalidChars == true) { strMessage = strMessage + "Your postcode can only be made up of letters, numbers and spaces.\n"; boolInvalidChars = false; }
            if(boolInvalidSpace == true) { strMessage = strMessage + "Your postcode may not begin or end with a space.\n"; }
        }

        //Check country.
        if(checkSelectBox(objCountry) == false) {
            strMessage = strMessage + "You must select your country from the dropdown list.\n";
            boolValid = false;
        }

        //Check telephone validity.
        if(strTelephone.length < 6) {
            strMessage = strMessage + "Your telephone number must be entered in order to continue.\n";
            boolValid = false;
        }
        if(strTelephone.length > 0) {
            //Check characters of number.
            for (intIndex = 0; intIndex < strTelephone.length; intIndex++) {
                if (strValidTelNumbers.search(strTelephone.charAt(intIndex)) == -1) {
                    boolInvalidChars = true;
                    boolValid = false;
                }
            }
            if(boolInvalidChars == true) { strMessage = strMessage + "Your telephone number can only be made up of numbers and spaces.\n"; boolInvalidChars = false; }
        }

        //Check fax validity.
        if(strFax.length > 0) {
            //Check characters of number.
            for (intIndex = 0; intIndex < strFax.length; intIndex++) {
                if (strValidTelNumbers.search(strFax.charAt(intIndex)) == -1) {
                    boolInvalidChars = true;
                    boolValid = false;
                }
            }
            if(boolInvalidChars == true) { strMessage = strMessage + "Your fax number can only be made up of numbers and spaces.\n"; boolInvalidChars = false; }
        }

        //Check email validity.
        if(strEmail.length < 6) {
            strMessage = strMessage + "Your email address must be entered in order to continue.\n";
            boolValid = false;
        }
        if(strEmail.length > 0) {
            //Check characters of number.
            for (intIndex = 0; intIndex < strEmail.length; intIndex++) {
                if (strValidEmailChars.search(strEmail.charAt(intIndex)) == -1) {
                    boolInvalidChars = true;
                    boolValid = false;
                }
            }
            if(boolInvalidChars == true) {
                strMessage = strMessage + "Please ensure you have entered a complete and valid email address.\n"; boolInvalidChars = false;
            }
            else {
                arrEmail = strEmail.split(".");
                if(arrEmail.length < 2) {
                    strMessage = strMessage + "Please ensure you have entered a complete and valid email address.\n";
                    boolValid = false;
                }
                else {
                    arrEmail = strEmail.split("@");
                    if(arrEmail.length < 2) {
                        strMessage = strMessage + "Please ensure you have entered a complete and valid email address.\n";
                        boolValid = false;
                    }
                }
            }
        }

        if(boolValid==false) {alert(strMessage);}
        return boolValid;
    }

    //function to check password.
    function checkPassword(strPassword, strConfirmPassword)
    {
        var boolValid = true;
        var boolInvalidChars;
        var strValidChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.";

        //Check length of password.
        if(strPassword.length<4) {
            alert("Please enter a password for accessing the NewNet customer management interface.\nYour password must be at least 4 characters long.")
            boolValid = false;
        }

        //Compare password and confirmed password.
        if(strPassword!=strConfirmPassword) {
            alert("Please ensure that you correctly enter your chosen password in the password confirmation textbox.");
            boolValid = false;
        }
        else {
            //Check characters of password.
            for (intIndex = 0; intIndex < strPassword.length; intIndex++) {
                if (strValidChars.search(strPassword.charAt(intIndex)) == -1) {
                    boolInvalidChars = true;
                    boolValid = false;
                }
            }
            if(boolInvalidChars==true) { alert("The password you have entered uses invalid characters. Please use letters and numbers only."); boolInvalidChars=false; }
        }

        return boolValid;
    }

    //function to check card details.
    function checkCardDetails(strCardHolder, strCardNumber, objStartMonth, objStartYear, objExpiryMonth, objExpiryYear, objCardType, strIssueNumber, strCVVCode, strTermsAgreed)
    {
        var boolValid = true;
        var strValidNumbers = "0123456789";
        var strMessage = "";
        var boolInvalidChars;
        var intIndex;
        var dteToday = new Date();

        //Check card holder.
        if(strCardHolder.length<3) {
            strMessage = "The name of the card holder must be entered.\n";
            boolValid = false;
        }

        //Check card number.
        if(strCardNumber.length<12) {
            strMessage = strMessage + "The full card number must be entered.\n";
            boolValid = false;
        }
        else {
            //Check characters of card number.
            for (intIndex = 0; intIndex < strCardNumber.length; intIndex++) {
                if (strValidNumbers.search(strCardNumber.charAt(intIndex)) == -1) {
                    boolInvalidChars = true;
                    boolValid = false;
                }
            }
            if(boolInvalidChars==true) { strMessage = strMessage + "The card number you have entered uses invalid characters. Please use numbers only with no spaces.\n"; }
        }

        //Check start date.
        if(objStartMonth.selectedIndex < 1 || objStartYear.selectedIndex < 1) {
            strMessage = strMessage + "The card start date must be entered.\n";
            boolValid = false;
        }
        else {
            //Check that start date falls before current date.
            var dteStart = new Date(objStartYear.value, objStartMonth.value, 01);
            if(dteToday-dteStart < 0) {
                strMessage = strMessage + "The start date has not yet been reached.\n";
                boolValid = false;
            }
        }

        //Check expiry date.
        if(objExpiryMonth.selectedIndex < 1 || objExpiryYear.selectedIndex < 1) {
            strMessage = strMessage + "The card expiry date must be entered.\n";
            boolValid = false;
        }
        else {
            //Check that expiry date falls after current date.
            var dteExpiry = new Date(objExpiryYear.value, objExpiryMonth.value, 01);
            if(dteExpiry-dteToday < 0) {
                strMessage = strMessage + "The card has already expired.\n";
                boolValid = false;
            }
        }

        //Check card type.
        if(objCardType.selectedIndex < 1) {
            strMessage = strMessage + "The card type must be selected.\n";
            boolValid = false;
        }

        //Check issue number.
        if(strIssueNumber.length>1) {
            //Check characters of issue number.
            for (intIndex = 0; intIndex < strIssueNumber.length; intIndex++) {
                if (strValidNumbers.search(strIssueNumber.charAt(intIndex)) == -1) {
                    boolInvalidChars = true;
                    boolValid = false;
                }
            }
            if(boolInvalidChars==true) { strMessage = strMessage + "The issue number you have entered uses invalid characters. Please use numbers only with no spaces.\n"; boolInvalidChars = false; }
        }

        //Check CVV number.
        if(strCVVCode.length < 3 || strCVVCode.length > 3) {
            strMessage = strMessage + "The CVV code for the card must be entered. \nThe CVV code is the last three digits of the number on the card signature bar.\n";
            boolValid = false;
        }
        else {
            //Check characters of CVV number.
            for (intIndex = 0; intIndex < strCVVCode.length; intIndex++) {
                if (strValidNumbers.search(strCVVCode.charAt(intIndex)) == -1) {
                    boolInvalidChars = true;
                    boolValid = false;
                }
            }
            if(boolInvalidChars==true) { strMessage = strMessage + "The CVV code you have entered uses invalid characters. Please use numbers only with no spaces.\n"; }
        }

        if(boolValid==false) { alert(strMessage); }
        return boolValid;
    }

    //function to check that a value in the specified select box has been selected.
    function checkSelectBox(objSelectBox)
    {
        var boolSelected = true;

        //Check the selected index of the select box.
        if (objSelectBox.selectedIndex < 1) {
            boolSelected = false;
        }

        return boolSelected;
    }