In this example we are going to show you how to how to insert Multiple Checkbox value in CodeIgniter framework MySQL PHP.
Here we using 3 files for insert Multiple Checkbox value in CodeIgniter framework MySQL PHP:
<?php 
	class Crud extends CI_Controller 
	{
		public function __construct()
		{
			parent::__construct();/* call CodeIgniter's default Constructor */
			$this->load->database();/* load database libray manually */
			$this->load->model('Crud_model');/* load Model */
		}
		public function multicheck()
		{ 
			$this->load->view('multicheck_insert');
			if(isset($_POST['save']))
			{
				$user_id=1;/* Pass the userid here */
				$checkbox = $_POST['check']; 
				for($i=0;$i<count($checkbox);$i++){
					$category_id = $checkbox[$i];
					$this->Crud_model->multisave($user_id,$category_id);/* Call the modal */
					
				}
				echo "Data added successfully!";
			}
		}
		
	}
?>
<?php
class Crud_model extends CI_Model 
{
	function multisave($user_id,$category)
	{
		$query="insert into user_cat values($user_id,$category)";
		$this->db->query($query);
	}
	
}
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<form method="post" action="">
	<input type="checkbox" id="checkItem" name="check[]" value="1">Car<br>
	<input type="checkbox" id="checkItem" name="check[]" value="2">Bike<br>
	<input type="checkbox" id="checkItem" name="check[]" value="3">Cycle<br>
	<button type="submit" class="btn btn-primary" style="width:200px" name="save">Submit</button>
</form>
</body>
</html>
Run the program on your browser with URL:
http://localhost/codeIgniter/index.php/Crud/multicheck
Here codeIgniter is my folder name. Put your folder name instead of codeIgniter.Rest of things are same.