What are the potential pitfalls of using multiple checkboxes with the same name in PHP forms?

When using multiple checkboxes with the same name in PHP forms, the issue arises when trying to retrieve the values of the checkboxes in the backend. If multiple checkboxes with the same name are checked, PHP will only recognize the last checkbox checked and ignore the rest. To solve this issue, you can append "[]" to the checkbox name in the HTML form, which will allow PHP to treat the checkboxes as an array and retrieve all the values. 

<form method="post">
    <input type="checkbox" name="colors[]" value="red"> Red
    <input type="checkbox" name="colors[]" value="blue"> Blue
    <input type="checkbox" name="colors[]" value="green"> Green
    <input type="submit" name="submit" value="Submit">
</form>

<?php
if(isset($_POST['submit'])) {
    if(isset($_POST['colors'])) {
        $selectedColors = $_POST['colors'];
        foreach($selectedColors as $color) {
            echo $color . "<br>";
        }
    }
}
?>

Keywords

PHP checkboxes forms array validation

Related Questions