jQuery AJAX从PHP中获取字段

The following code sends some data to a PHP file. That PHP file encodes to a JSON object and echoes three variables error, success, and action.

However, neither the success function here, nor the error function appear to be returning that JSON object.

How would one get the values for these three keys back.

$.ajax({ 
     type: 'POST',
     contentType: "application/json; charset=utf-8",
     url: ua['url'], 
     data: { sconnect: 'email', email : $('#semail').val(), hack:86 }, 
     dataType: 'json',
     success: function (data) {
         alert(data['success']); alert(data['error']); alert(data['action']);
     },
     error: function(data){
         alert(data['success']); alert(data['error']); alert(data['action']);
     }
});