What are common pitfalls when trying to save values from dropdown menus and checkboxes in PHP forms?

Common pitfalls when trying to save values from dropdown menus and checkboxes in PHP forms include not properly handling the selected values and not using the correct syntax to retrieve the values from the form. To solve this issue, make sure to use the appropriate method to retrieve the selected values from dropdown menus and checkboxes, such as using $_POST for form submissions.

// Dropdown menu example
$selected_option = $_POST['dropdown_menu'];

// Checkbox example
$checkbox_values = isset($_POST['checkbox_name']) ? $_POST['checkbox_name'] : [];