function eraseBoard() {
    var element = document.getElementById('form-board');
    element.style.color = '#000';
    var first = document.getElementById('first-board');
    if (first.value == 'true') {
        element.value = '';
        first.value = 'false';
    }
}

function eraseEmail() {
    var element = document.getElementById('form-email');
    element.style.color = '#000';
    var first = document.getElementById('first-email');
    if (first.value == 'true') {
        element.value = '';
        first.value = 'false';
    }
}