function AjaxRequest(url, callback_function) {

  var req = null;

  var msxmlhttp = new Array(

    'Msxml2.XMLHTTP.5.0',

    'Msxml2.XMLHTTP.4.0',

    'Msxml2.XMLHTTP.3.0',

    'Msxml2.XMLHTTP',

    'Microsoft.XMLHTTP');

  for (var i = 0; i < msxmlhttp.length; i++) {

    try {

      req = new ActiveXObject(msxmlhttp[i]);

    } catch (e) {

      req = null;

    }

  }



  if(!req && typeof XMLHttpRequest != "undefined") {

    req = new XMLHttpRequest();

  }

  if (req != null) {

    req.open("POST", url, true);

    req.onreadystatechange = function() {

      if ((req.readyState == 4) && (req.status == 200)) {

        var json = req.responseText.parseJSON();

        var callback = callback_function + '(json)';

        eval(callback);

      }

    }

    req.send(null);

    delete req;

  }

  return true;

}



function UpdateForm(objects) {

  document.forms['add_frm']['fetch_meta'].disabled = false;

  for (var i in objects) {

    if (i != "toJSONString") {

      if (document.forms['add_frm'][i]) {

        document.forms['add_frm'][i].value = objects[i];

      }

    }

  }

}



function FetchMeta() {

  var url = document.forms['add_frm']['url'].value;

  document.forms['add_frm']['fetch_meta'].disabled = true;

  AjaxRequest('ajax.php?cmd=fetch_meta&url=' + url, 'UpdateForm');

}



function UpdateSubCategory(objects) {

  document.getElementById(objects['div_tag']).innerHTML = objects['select_box'];

}



function FetchSubCategory(cat, selected_cat, div_tag) {

  document.getElementById(div_tag).innerHTML = "loading...";

  AjaxRequest('ajax.php?cmd=fetch_sub_category&cat=' + cat + "&selected_cat=" + selected_cat+ "&div_tag=" + div_tag, 'UpdateSubCategory');

}



function UpdatePricing(objects) {

  document.getElementById("listing_type_div").innerHTML = objects;

}



function FetchPricing() {

  var cat = document.forms['add_frm']['cat'].options[document.forms['add_frm']['cat'].selectedIndex].value;

  var cat1 = document.forms['add_frm']['add_cat1'].options[document.forms['add_frm']['add_cat1'].selectedIndex].value;

  var cat2 = document.forms['add_frm']['add_cat2'].options[document.forms['add_frm']['add_cat2'].selectedIndex].value;

  if (document.forms['add_frm']['periodprice']) {

    var periodprice = document.forms['add_frm']['periodprice'].options[document.forms['add_frm']['periodprice'].selectedIndex].value;

  }

  document.getElementById("listing_type_div").innerHTML = "loading...";

  AjaxRequest('ajax.php?cmd=fetch_pricing&cat=' + cat + "&cat1=" + cat1 + "&cat2=" + cat2 + "&periodprice=" + periodprice, 'UpdatePricing');

}