var http_request = false;
var thisTargetObject = false;
var evalReturn = false;

function displayError(errorMessage) {
  window.alert(errorMessage);
}

function alertContents() {
  if (http_request.readyState == 4) {
    if (http_request.status == 200) {
      result = http_request.responseText;
      if (evalReturn == true) {
        start = (result.indexOf("<script>") + 31);
        end = (result.lastIndexOf("</script>",start) - 8);
        evalString = result.slice(start,end);
        if (start && end && start != end) {
          eval(evalString);
        }
      }
      document.getElementById(thisTargetObject).innerHTML = result;
    } else {
      displayError("There was a problem with the request.");
    }
  }
}

function ajaxPostExecute(targetObject, url, parameters) {
  http_request = false;
  thisTargetObject = targetObject;
  if (window.XMLHttpRequest) { // Mozilla, Safari,...
    http_request = new XMLHttpRequest();
    if (http_request.overrideMimeType) {
      http_request.overrideMimeType('text/html');
    }
  } else if (window.ActiveXObject) { // IE
    try {
      http_request = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
      try {
        http_request = new ActiveXObject("Microsoft.XMLHTTP");
      } catch (e) {}
    }
  }
  if (!http_request) {
    displayError('Cannot create XMLHTTP instance');
    return false;
  }
  http_request.onreadystatechange = alertContents;
  http_request.open('POST', url, true);
  http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
  http_request.setRequestHeader("Content-length", parameters.length);
  http_request.setRequestHeader("Connection", "close");
  http_request.send(parameters);
}

function ajaxPost(fromForm, targetObject, targetPage) {
  var getstr = "";

  obj = document.getElementById(fromForm).getElementsByTagName('input');
  for (i = 0; i < obj.length; i++) {
    if (obj[i].type == "text") {
      getstr += obj[i].name + "=" + obj[i].value + "&";
    }
    if (obj[i].type == "password") {
      getstr += obj[i].name + "=" + obj[i].value + "&";
    }
    if (obj[i].type == "hidden") {
      getstr += obj[i].name + "=" + obj[i].value + "&";
    }
    if (obj[i].type == "button") {
      getstr += obj[i].name + "=" + obj[i].value + "&";
    }
    if (obj[i].type == "file") {
      getstr += obj[i].name + "=" + obj[i].value + "&";
    }
    if (obj[i].type == "image") {
      getstr += obj[i].name + "=" + obj[i].value + "&";
    }
    if (obj[i].type == "reset") {
      getstr += obj[i].name + "=" + obj[i].value + "&";
    }
    if (obj[i].type == "submit") {
      getstr += obj[i].name + "=" + obj[i].value + "&";
    }
    if (obj[i].type == "checkbox") {
      if (obj[i].checked) {
        getstr += obj[i].name + "=" + obj[i].value + "&";
      } else {
        getstr += obj[i].name + "=&";
      }
    }
    if (obj[i].type == "radio") {
      if (obj[i].checked) {
        getstr += obj[i].name + "=" + obj[i].value + "&";
      }
    }
  }
 
  getstr += "ajax=1&";

  obj = document.getElementById(fromForm).getElementsByTagName('textarea');
  for (i = 0; i < obj.length; i++) {
    getstr += obj[i].name + "=" + encodeURI(obj[i].value) + "&";
  }

  obj = document.getElementById(fromForm).getElementsByTagName('select');
  for (i = 0; i < obj.length; i++) {
    getstr += obj[i].name + "=" + obj[i].options[obj[i].selectedIndex].value + "&";
  }

  ajaxPostExecute(targetObject, targetPage, getstr);
}

function ajaxGet(targetObject, targetPage, eval) {
  thisTargetObject = targetObject;
  evalReturn = eval;
  if (window.XMLHttpRequest) { // Mozilla, Safari,...
    http_request = new XMLHttpRequest();
    if (http_request.overrideMimeType) {
      http_request.overrideMimeType('text/html');
    }
  } else if (window.ActiveXObject) { // IE
    try {
      http_request = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
      try {
        http_request = new ActiveXObject("Microsoft.XMLHTTP");
      } catch (e) {}
    }
  }
  if (!http_request) {
    displayeError('Cannot create XMLHTTP instance');
    return false;
  }
  http_request.onreadystatechange = alertContents;
  http_request.open("GET", targetPage, true);
  http_request.send(null);
}