html checkbox
<!--
You can also group multiple checkboxes by giving them the same "name".
When posted to PHP, all the checked boxes' values will appear in the
$_POST array under an index with the same name as your checkboxes.
E.g. if we check "bananas" and "apples" below and post the form then
our $_POST array will look something like this:
['fruit' => ['bananas', 'apples']]
-->
<form>
<label>
<span>Bananas</span>
<input type="checkbox" name="fruit[]" value="bananas">
</label>
<label>
<span>Apples</span>
<input type="checkbox" name="fruit[]" value="apples">
</label>
<label>
<span>Grapes</span>
<input type="checkbox" name="fruit[]" value="grapes">
</label>
<button type="submit">Submit</button>
</form>