function validateFormOnSubmit(theForm) {
var reason = "";
//reason += validatefirstname(theForm.first_name);
 // reason += validatelastname(theForm.last_name);
  reason += validateEmail(theForm.email);
 //  reason += validatebirthyear(theForm.birth_year);
 // reason += validatePassword(theForm.password);
  reason += validateTivia(theForm.triviaquestion);
  
 // reason += validatePhone(theForm.phone);
 // reason += validateEmpty(theForm.city);
 // reason += validateEmpty(theForm.name);
 
//reason += validateEmpty(theForm.password);
//reason += validateEmpty(theForm.mtype);


  if (reason != "") {
    alert("Some fields need correction:\n" + reason);
    return false;
  }

  return true;
}

function validateEmpty(fld) {
    var error = "";
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = "The required field has not been filled in.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}
function validateTivia(fld) {
    var error = "";
    if (fld.value != 4) {
        fld.style.background = 'Yellow'; 
        error = "The trivia question's anser is wrong.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}
function validatelastname(fld) {
    var error = "";
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = "You didn't enter your last name.\n";
    } else {
        fld.style.background = 'White';
    }
    return error;  
}
function validatefirstname(fld) {
    var error = "";
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = "You didn't enter your first name.\n";
    } else {
        fld.style.background = 'White';
    }
    return error;  
}
function validatebirthyear(fld) {
    var error = "";
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = "You didn't enter your birth year.\n";
    } else {
        fld.style.background = 'White';
    }
    return error;  
}
function validateEmpty(fld) {
    var error = "";
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = "The required field has not been filled in.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}

function validateUsername(fld) {
    var error = "";
    var illegalChars = /\W/; // allow letters, numbers, and underscores
 
    if (fld.value == "") {
        fld.style.background = 'Yellow'; 
        error = "You didn't enter your last names.\n";
    } else if ((fld.value.length < 5) || (fld.value.length > 15)) {
        fld.style.background = 'Yellow'; 
        error = "The username is the wrong length.\n";
    } else if (illegalChars.test(fld.value)) {
        fld.style.background = 'Yellow'; 
        error = "The username contains illegal characters.\n";
    } else {
        fld.style.background = 'White';
    }
    return error;
}

function validatePassword(fld) {
    var error = "";
    var illegalChars = /[\W_]/; // allow only letters and numbers 
 
    if (fld.value == "") {
        fld.style.background = 'Yellow';
        error = "You didn't enter a password.\n";
    } else if ((fld.value.length < 1) || (fld.value.length > 15)) {
        error = "The password is too long - 15 characters max. \n";
        fld.style.background = 'Yellow';
    } else if (illegalChars.test(fld.value)) {
        error = "The password contains illegal characters - only letters and numbers.\n";
        fld.style.background = 'Yellow';
    } else {
        fld.style.background = 'White';
    }
   return error;
}   


function trim(s)
{
  return s.replace(/^\s+|\s+$/, '');
}

function validateEmail(fld) {
    var error="";
    var tfld = trim(fld.value);                        // value of field with whitespace trimmed off
    var emailFilter = /^[^@]+@[^@.]+\.[^@]*\w\w$/ ;
    var illegalChars= /[\(\)\<\>\,\;\:\\\"\[\]]/ ;
   
    if (fld.value == "") {
        fld.style.background = 'Yellow';
        error = "You didn't enter an email address.\n";
    } else if (!emailFilter.test(tfld)) {              //test email for illegal characters
        fld.style.background = 'Yellow';
        error = "Please enter a valid email address.\n";
    } else if (fld.value.match(illegalChars)) {
        fld.style.background = 'Yellow';
        error = "The email address contains illegal characters.\n";
    } else {
        fld.style.background = 'White';
    }
    return error;
}

function validatePhone(fld) {
    var error = "";
    var stripped = fld.value.replace(/[\(\)\.\-\ ]/g, '');    

   if (fld.value == "") {
        error = "You didn't enter a phone number.\n";
        fld.style.background = 'Yellow';
    } else if (isNaN(parseInt(stripped))) {
        error = "The phone number contains illegal characters.\n";
        fld.style.background = 'Yellow';
    } else if (!(stripped.length == 10)) {
        error = "The phone number is the wrong length. Make sure you included an area code.\n";
        fld.style.background = 'Yellow';
    }
    return error;
}