function validateForm() {
    if ($('opt_domain1').checked == true) {
        if (validateDomainName_TLD($('domainname1').value)) {
            $('frmOrder').submit();
        } else {
            alert('The provided domain name is either invalid or contain invalid character(s).');
                $('domainname1').focus();
                $('domainname1').select();
        }
    } else {
        if (validateDomainName_NOTLD($('domainname2').value)) {
            $('frmOrder').submit();
        } else {
            alert('The provided domain name is either invalid or contain invalid character(s).');
            $('domainname2').focus();
            $('domainname2').select();
        }
    }
}

function validateDomainName_TLD(domainname) {
    if (!domainname.match(/^([a-z0-9]([-a-z0-9]*[a-z0-9])?.)+((a[cdefgilmnoqrstuwxz]|aero|arpa)|(b[abdefghijmnorstvwyz]|biz)|(c[acdfghiklmnorsuvxyz]|cat|com|coop)|d[ejkmoz]|(e[ceghrstu]|edu)|f[ijkmor]|(g[abdefghilmnpqrstuwy]|gov)|h[kmnrtu]|(i[delmnoqrst]|info|int)|(j[emop]|jobs)|k[eghimnprwyz]|l[abcikrstuvy]|(m[acdghklmnopqrstuvwxyz]|mil|mobi|museum)|(n[acefgilopruz]|name|net)|(om|org)|(p[aefghklmnrstwy]|pro)|qa|r[eouw]|s[abcdeghijklmnortvyz]|(t[cdfghjklmnoprtvwz]|travel)|u[agkmsyz]|v[aceginu]|w[fs]|y[etu]|z[amw])$/i)) {
        return false;
    } else {
        return true;
    }
}

function validateDomainName_NOTLD(domainname) {
    if (!domainname.match(/^([a-z0-9]([-a-z0-9]*[a-z0-9])?)+$/i)) {
        return false;
    } else {
        return true;
    }
}