没有PHP的jQuery消息系统怎么办？

commentajax.php

POST

PUT

$.ajax({
type: \"POST\",
url: \"http://www.xxx.com/json\",
data: dataString,
cache: false,
success: function(html){
    $(\"ol#update\").append(html);
    $(\"ol#update li:last\").fadeIn(\"slow\");
    document.getElementById(\'comment\').value=\'\';
    $(\"#name\").focus();
    $(\"#flash\").hide();
}
});

$.getJSON(\'http://www.xxx.com/json\' , function(data) { ... });

i have the server-side script in place

$.getJSON(\'http://www.xxx.com/json\' , function(data) { 
 for(i=0; i<data.comment.length; i++) {
   $(\".commentTitle\").html(data.comment[i].title);
   $(\".commentBody\").html(data.comment[i].text);
 }
});

because i want to post to a json file and then get the response from the same file.