<script type="text/javascript">
$(document).ready(function(){
$('#btnLogin').bind('click', loginToWebsite);
});
function loginToWebsite(){
     $.ajax({
     url: "login.php",
      type: "POST",
      data: "username=" + $("#username").val()+"&password=" + $("#password").val(),
    datatype:"json",
      success: function(status)
      {
        if(status.success == false)
        {
            $("#loginform").effect("shake", {times:2}, 100);
            $("#login_message")
                .attr('class', 'ui-state-error')
                .html('<strong>ERROR</strong>: Your details were incorrect.<br />');
        }
        else {
                 $("#login_message")
                .attr('class', 'ui-state-highlight')
                .html('<strong>PERFECT</strong>: You may proceed. Good times.<br />');
            }
      }
    });
}
</script>

<?php
if (isset($_POST['username'])&& isset($_POST['password']))
{
    if (login ($_POST['username'], $_POST['password'])){
        $data = array("success" => true);
        echo json_encode($data);
    }
    else {
        $data = array("success" => false);
        echo json_encode($data);
    }
}?>

if login = false
{
$data['success'] = false;
echo json_encode($data);
}
else {
$data['success'] = true;
echo json_encode($data);
}

if login = false
{
$data['success'] = false;
echo json_encode($data);
}
else {
$data['success'] = true;
echo json_encode($data);
}

<?php
    if (isset($_POST['username'])&& isset($_POST['password']))
    {
        if (login ($_POST['username'], $_POST['password'])){
            $data = array("success" => true);
            echo json_encode($data);
        }
        else {
            $data = array("success" => false);
            echo json_encode($data);
        }
    }?>