function checkNewsletterForm() {
    if (!check_myTextField(document.getElementById('firstname'),0) || !check_myTextField(document.getElementById('lastname'),0) || !check_myEmail(document.getElementById('email'))) {
        alert ('Please fill in all the fields and check to make sure that your email address has been correctly formatted.');
        return false;
    } else {
        return true;
    }
}

// Check input text field
function check_myTextField(myField,minLength) {
    if(myField.value=='' || myField.value.length<parseInt(minLength)) {
        myField.focus();
        return false;
    }
    return true;
}

// Check email field
function check_myEmail(myField) {
    if(check_myTextField(myField,6)) {
        var str = myField.value;
        var re = /^[\w-]+(\.[\w-]+)*@([\w-]+\.)+[a-zA-Z]{2,7}$/;
        if(!str.match(re)) {
            myField.focus();
            return false;
        }
        else return true;
    }
    else return false;
}