PHP需要复选框字段

Question

I have a form with multiple checkboxes. I want to allow the user to select at least 1 in each checkbox field, if the user does not check any of the options in the checkbox, a message will display "You have to select at least one." How do I do it? I have here some of my codes:

<div>
    <div><span class="font-2">Categories:</span></div>
</div>

<div class = "addinfo">
    <?php $categories = array('Breakfast', 'Lunch', 'Dinner', 'Snack', 'Grill', 'Buffet', 'Fast Food');
          $values = explode(',' , $row['categories']);
    ?>

    <?php foreach($categories as $category) {
        $cat='';
        foreach($values as $value){
        if($value == $category){
        $cat ="checked";    
    }

    ?>
    <input <?php echo $cat ?> type="checkbox" name="category[]" value="<?php echo $category?>"><?php echo $category?><br>
    <?php } 
    }?>
</div>  

form

<form method = "POST" action = "<?php echo base_url().'/index.php/AdminController/operation'?>">

AdminController

public function addResto(){
    $this->load->model('AdminModel');
    $this->AdminModel->insert();
    $this->getRestos();
}
public function operation(){

    if(isset($_POST['btn'])){
        if(empty($_POST['id'])){
            $this->addResto();
        }
        else{
            $this->updatingResto();
        }   
    }
}
public function updateResto($id){
    $this->load->model('AdminModel');
    $restaurantinfo['restaurantinfo']=$this->AdminModel->getResto($id);
    $this->load->view('admin/UpdateRestoPage',$restaurantinfo);
}

public function updatePage(){
    $this->load->view('admin/UpdateRestoPage');
}

public function updatingResto(){
    $id = $_POST['id'];
    $this->load->model('AdminModel');
    $this->AdminModel->update($id);

}

Answer 1

You should also check if there is a checkbox that is checked

public function operation(){
    if(isset($_POST['btn'])){
        if(empty($_POST['category'])){
            $this->load->view('YOUR_VIEW_FILE',array('error'=>'category'));
        }else if(empty($_POST['id'])){
            $this->addResto();
        }
        else{
            $this->updatingResto();
        }   
    }
}

your view file add a condition

<?php 
    if(!empty($error) && $error=="category"){
?>
    <script>alert("You have to select at least one.");</script>
<?php 
    } 
?>