Custom Form Validation - Phone

var oPhoneField = document.getElementsByName('Phone')[0]; //get Phone input element
var oErrorMessage = document.createElement('p'); //create paragraph that will contain the error message
var cHasDuplicates = /^\D*(\d)(?:\D*|\1)*$/; //regex for later use
oErrorMessage.classList = 'error-message'; //give error message paragraph class for optional styling via customCSS

//Conditional Error Messages
var cMessages = {
  charLength: 'Phone number must contain 3 to 32 characters',
  charContent: 'Phone number cannot contain a comma, period, or semicolon',
  charRepeated: 'Phone number cannot contain the same digits. ie "1111111111" is not an acceptable number',
  charConsecAsc: 'Phone number cannot contain more than 6 consecutive digits. ie "123456" is not an acceptable number',
  charConsecDesc: 'Phone number cannot contain more than 6 consecutive digits. ie "654321" is not an acceptable number',
  charDigitPerc: 'Phone number contains too many non-digit characters'
};

oPhoneField.addEventListener('blur', validatePhone);

function validatePhone() {
  var cPhoneVal = oPhoneField.value; //string value to validate against
  var bCharLength = cPhoneVal.length < 3 || cPhoneVal.length > 32; //sets acceptable length between 3 and 32
  var bCharContains = cPhoneVal.indexOf(',') > 0 || cPhoneVal.indexOf('.') > 0 || cPhoneVal.indexOf(';') > 0; //no commas, periods, or semi-colons
  var bCharDuplicate = cPhoneVal.length >= 9 && cHasDuplicates.test(cPhoneVal); //set length for acceptable repeated characters
  var bCharConsecAsc = consecDigits(cPhoneVal, 6, false); //set string, set consecutive number max, true - descending order -> false - ascending order
  var bCharConsecDesc = consecDigits(cPhoneVal, 6, true); //set string, set consecutive number max, true - descending order -> false - ascending order
  var bNonDigitLimit = calcNonDigits(cPhoneVal, .30); //set string, set acceptable percent of non-digit characters

  if (bCharLength) {
    printMessage(cMessages.charLength);
    return false;
  } else if (bCharContains) {
    printMessage(cMessages.charContent);
    return false;
  } else if (bCharDuplicate) {
    printMessage(cMessages.charRepeated);
    return false;
  } else if (bCharConsecAsc) {
    printMessage(cMessages.charConsecAsc);
    return false;
  } else if (bCharConsecDesc) {
    printMessage(cMessages.charConsecDesc);
    return false;
  } else if (bNonDigitLimit) {
    printMessage(cMessages.charDigitPerc);
    return false;
  } else {
    printMessage('');
    return true;
  }
}

//consecDigits() is based on a function created by stackoverflow user 'AGE'
//http://stackoverflow.com/questions/30928293/how-to-find-whether-specific-number-of-continuous-consecutive-numbers-are-contai
function consecDigits(str, consecutive, descending) {
  if (descending) {
    var cPhoneVal = reverseString(str);
  } else {
    var cPhoneVal = str;
  }

  var curr,
    prev,
    count = 0;
  for (var i = 0; i < cPhoneVal.length; ++i) {
    curr = parseInt(cPhoneVal.split('')[i]);
    if (isNumeric(curr)) {
      if (count === 0) {
        ++count;
      } else if (prev + 1 === curr) {
        ++count;
        if (count === consecutive) {
          return true;
        }
      }
      prev = curr;
    }
  }
  return false;
}

function reverseString(str) {
  var splitString = str.split("");
  var reverseArray = splitString.reverse();
  var joinArray = reverseArray.join("");
  return joinArray;
}

function isNumeric(n) {
  return !isNaN(parseFloat(n)) && isFinite(n);
}

function calcNonDigits(phoneVal, percent) {
  var cDigits = phoneVal.replace(/[^\d]/g, '');
  var iNonDigits = phoneVal.length - cDigits.length;
  var bTest = iNonDigits / phoneVal.length >= percent;
  if (bTest) return true;
  return false;
}

function printMessage(message) {
  oErrorMessage.innerHTML = '';
  oErrorMessage.innerHTML = message;
  oPhoneField.parentNode.appendChild(oErrorMessage);
}