I noticed that the following code doesn't work. When I remove `, "json");` at the end of it, it works but i just get failure. I followed it to jquery spec on the site. Any idea why the `$.post` method won't work/enter? 

The reason i know it wont enter $.post is because `alert(form.serialize());` doesnt get called.

In my PHP i am returning the following when it posts:

```
        $arr = array('status' => 'SUCCESS');

        echo json_encode($arr);
         exit();

```

This is my ajax below:

```
var form = $('#lines');
        $.post('', form.serialize(), function(json) {
            alert(form.serialize());

            if(json.status === 'SUCCESS') {
                alert(json);
                console.log('success');
            } else {
                alert(json);
                console.log('failure');
            }
        }, "json");

```

If I remove the json part at the end, it just returns the entire HTML of the page.