function formValidator()
{
    // set up array to hold error messages
    this.errorList = new Array;
    // set up object methods
    this.isEmpty = isEmpty;
    this.isNumber = isNumber;
    this.isAlphabetic = isAlphabetic;
    this.isAlphaNumeric = isAlphaNumeric;
    this.isWithinRange = isWithinRange;
    this.isEmailAddress = isEmailAddress;
    this.isChecked = isChecked;
    this.raiseError = raiseError;
    this.numErrors = numErrors;
    this.displayErrors = displayErrors;
}

// check to see if input is whitespace only or empty

function isEmpty(val)
{
    if (val.match(/^s+$/) || val == "")
        return true;
    else
        return false;
}

// check to see if input is number
function isNumber(val)
{
    if (isNaN(val))
        return false;
    else
        return true;
}

// check to see if value is within min and max
function isWithinRange(val, min, max)
{
    if (val >= min && val <= max)
        return true;
    else
        return false;
}

// check to see if form value is checked
function isChecked(obj)
{
    if (obj.checked)
        return true;
    else
        return false;
}

// check to see if input is alphabetic
function isAlphabetic(val)
{
    if (val.match(/^[a-zA-Z]+$/))
        return true;
    else
        return false;
}

// check to see if input is alphanumeric
function isAlphaNumeric(val)
{
    if (val.match(/^[a-zA-Z0-9]+$/))
        return true;
    else
        return false;
}

// check to see if input is a valid email address
function isEmailAddress(val)
{
    if (val.match(/^([a-zA-Z0-9])+([.a-zA-Z0-9_-])*@([a-zA-Z0-9_-])+(.[a-zA-Z0-9_-]+)+/))
        return true;
    else
        return false;
}

// add an error to error list
function raiseError(msg)
{
    this.errorList[this.errorList.length] = msg;
}

// display all errors
// iterate through error array and print each item
function displayErrors()
{
    for (x=0; x<this.errorList.length; x++)
        alert("Error: " + this.errorList[x]);
}

// return number of errors in error array
function numErrors()
{
    return this.errorList.length;
}