An Error Was Encountered in CI forms - php

Question

Iam a newbie in Codeigniter , Iam learning it from watching videos , the instructor did the same what I did , But it gives me an error like this "The action you have requested is not allowed." ,and it worked with him, I don't know why, any help ! .
this is my Controller code
public function index(){
if($this->input->post('submit')){
echo $this->input->post('first_name');
}
$this->load->view('forms');
}
this is my View code
<form method="POST">
<input type="text" name="first_name" />
<input type="submit" name=submit" />
</form>

Answer 1

Use form_open() helper which automatically adds hidden input with CSRF value.
So your view should be:
<?php echo form_open('action_url'); ?>
<input type="text" name="first_name" />
<input type="submit" name=submit" />
<?php echo form_close(); ?>
Disabling CSRF protection also works but it's a bad idea.

Answer 2

you almost right, you need to add some parts like action in your form, and isset or empty in your controller like
class Test_form extends CI_Controller{
public function __construct(){
parent::__construct();
}
public function index(){
$this->load->view('form_test');
}
//using your example. good
public function check_form(){
if( isset($this->input->post('first_name', TRUE))){
echo "success <br>$$this->input->post('fisrt_name', TRUE)";
}
else{
echo "error";
}
}
//using form_validation. best
public function check_form_validation(){
$this->load->library('form_validation');
$this->form_validation->set_rules('first_name', 'first Name', 'trim|required|xss_clean');
if( ! $this->form_validation->run()){
echo "error <br>" . validation_errors();
}
else{
echo "success <br>$$this->input->post('fisrt_name', TRUE)";
}
}
}
form_test.php
first method
<form method="post" action="<?= base_url()?>index.php/test_form/check_form">
<input type="text" name="first_name">
<input type="submit" value="test">
</form>
<hr>
second method
<form method="post" action="<?= base_url()?>index.php/test_form/check_form_validation">
<input type="text" name="first_name">
<input type="submit" value="test">
</form>