[jQuery] Jquery Ajax vs base Ajax approach

[bookme]

Hi,

Jquery is gr8 I agreed.

But when I am working on a registration page then this jquery is not
providing me seamless effect.

There is two select box - drop down
1 State
2 City
when ever a user select a state correspondingly city comes in city
drop down.

I used two apprach for this

1 Ajax- Jquery
$.ajax({
  type: "POST",
  url: "<?php //echo $html->url('/users/city') ?>",
  data: "state_id=" + escape(state_value),
  success: function(html){
    $("#id_city").html(html);
  }

2 Base Ajax approach

Create a HTTP object : httpObject
Open http connection
httpObject.open("GET", url,  true);
httpObject.send(null);
httpObject.onreadystatechange = setOutput;
getting response on httpObject.readyState == 4


Base Ajax approach  return me better results then jquery.

But I need seemless - more better results...

Can somebody tell me how should I get more better results for this?

Should I follow jquery instead of Base AJAX approach?

Thanks