function validateForm(theForm) {

  var reason = "";
  
  reason += validateEmpty(theForm.fullname, "Fullname");
  reason += validateEmail(theForm.email);
  reason += validateEmpty(theForm.subject, "Subject");
  reason += validateEmpty(theForm.message, "Message");


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

  return true;
}

function validateEmpty(fld, name) {
    error = "";
 
	fld.style.background = 'White';
 
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = name+" field has not been filled in.\n"
    } else {
        fld.style.background = 'White';
    }
	
	
    return error;  
}

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

function validateEmail(fld) {
    error="";
	
	fld.style.background = 'White';
		
    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;
}