如何让checkbox删除表单中的“必需”验证

input:invalid + span::before {
    content: none;
}

<form>
    <input type="checkbox" required>
    <span class="error-message">This field is required</span>
    <button type="submit">Submit</button>
</form>

<form novalidate>
    <input type="checkbox" required>
    <button type="submit">Submit</button>
</form>

<form id="myForm">
    <input type="checkbox" id="myCheckbox">
    <button type="submit">Submit</button>
</form>

<script>
document.getElementById('myForm').addEventListener('submit', function(event) {
    if (!document.getElementById('myCheckbox').checked) {
        alert('Checkbox must be checked');
        event.preventDefault();
    }
});
</script>