表单提交复选框（checkbox）注意事项

<form action="a.php" method="post">
    <input type="checkbox" name="hobby[]" value="唱歌"/>唱歌
    <input type="checkbox" name="hobby[]" value="跳舞"/>跳舞
    <input type="checkbox" name="hobby[]" value="轮滑"/>轮滑
    <input type="checkbox" name="hobby[]" value="lol"/>lol
    <br/>
    <input type="submit" value="提交">
</form>

<?php 
    $hobby=$_POST[‘hobby‘];
    echo print_r($hobby);
?>