function validateFormOnSubmit(theForm) {
var reason = "";

reason += validateEmptyFirstName(theForm.FirstName);
reason += validateEmptyLastName(theForm.LastName);
reason += validateEmptyMailingAddress(theForm.MailingAddress);
reason += validateEmptyCity(theForm.City);
reason += validateEmptyState(theForm.State);
reason += validateEmptyZip(theForm.Zip);
reason += validateEmail(theForm.Email);
reason += validatePhone(theForm.Phone);
reason += validateEmptyContribution(theForm.Contribution);
reason += validateEmptyMethodofGiving(theForm.MethodofGiving);


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

  return true;
}


function validateEmptyFirstName(fld) {
    var error = "";
  
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = "First Name has not been filled in.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;   
}

function validateEmptyLastName(fld) {
    var error = "";
  
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = "Last Name has not been filled in.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;   
}


function validateEmptyMailingAddress(fld) {
    var error = "";
  
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = "Mailing Address has not been filled in.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;   
}


function validateEmptyCity(fld) {
    var error = "";
  
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = "City has not been filled in.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;   
}

function validateEmptyState(fld) {
    var error = "";
  
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = "State has not been selected.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;   
}

function validateEmptyZip(fld) {
    var error = "";
  
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = "Zip has not been filled in.\n"
    } 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';
    } 
    return error;
}


function validateEmptyContribution(fld) {
    var error = "";
    var stripped = fld.value.replace(/[\(\)\.\-\ ]/g, '');  
    
if (fld.value == "") {
        error = "Please fill in the amount of your contribution.\n";
        fld.style.background = 'Yellow';
    } else if (isNaN(parseInt(stripped))) {
        error = "Your contribution contains illegal characters.\n";
        fld.style.background = 'Yellow';
    } 
    return error;
}


function validateEmptyMethodofGiving(fld) {
    var error = "";
  
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = "Please select your method of giving.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;   
}