The CI framework does not respond to the expression commit. why? how can this problem be solved?

The CI framework does not respond to the expression submission. why? this is the code block of the form in the view & lt; form & nbsp; actionlocalhost ~ ChrisfuCIindex. phploginchecklogin & nbsp; methodpost & gt; & lt; h3 CI framework, which indicates that the submission does not respond. why?
This is the form code block in the view.

This is the php code

 class Login extends CI_Controller{
function index(){
$this->load->view('index');
}
function checklogin(){
$this->load->model('test_m');
$user=$this->test_m->user_select($_POST['name']);

if($user){
if($user[0]->upass==$_POST['pword']){
echo "password right";
$this->load->library('session');
$arr=array('uid'=>$user[0]->uid);
$this->session->set_userdata($arr);
echo "
";
echo $this->session->userdata('uid');
}else{
echo "password wrong";
}
}else{
echo "user not exist";
}
}
}

?>

------ Solution --------------------
Change the name of the submit button and use firebug to monitor the network.