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

	reason += validateEmpty(theForm.firstname);
	reason += validateEmpty(theForm.lastname);
 	reason += validateEmpty(theForm.phone);
	reason += validateEmail(theForm.email);
     
	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 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;
}