function getDataReturnText(url, callback)
{ 
  var XMLHttpRequestObject = false; 

  if (window.XMLHttpRequest) {
    XMLHttpRequestObject = new XMLHttpRequest();
  } else if (window.ActiveXObject) {
    XMLHttpRequestObject = new 
     ActiveXObject("Microsoft.XMLHTTP");
  }

  if(XMLHttpRequestObject) {
    XMLHttpRequestObject.open("GET", url); 

    XMLHttpRequestObject.onreadystatechange = function() 
    { 
      if (XMLHttpRequestObject.readyState == 4 && 
        XMLHttpRequestObject.status == 200) { 
          callback(XMLHttpRequestObject.responseText); 
          delete XMLHttpRequestObject;
          XMLHttpRequestObject = null;
      } 
    } 

    XMLHttpRequestObject.send(null); 
  }
}

function getDataReturnXml(url, callback)
{ 
  var XMLHttpRequestObject = false; 

  if (window.XMLHttpRequest) {
    XMLHttpRequestObject = new XMLHttpRequest();
  } else if (window.ActiveXObject) {
    XMLHttpRequestObject = new 
     ActiveXObject("Microsoft.XMLHTTP");
  }

  if(XMLHttpRequestObject) {
    XMLHttpRequestObject.open("GET", url); 

    XMLHttpRequestObject.onreadystatechange = function() 
    { 
      if (XMLHttpRequestObject.readyState == 4 && 
        XMLHttpRequestObject.status == 200) { 
          callback(XMLHttpRequestObject.responseXML); 
          delete XMLHttpRequestObject;
          XMLHttpRequestObject = null;
      } 
    } 

    XMLHttpRequestObject.send(null); 
  }
}

function postDataReturnText(url, data, callback)
{ 
  var XMLHttpRequestObject = false; 

  if (window.XMLHttpRequest) {
    XMLHttpRequestObject = new XMLHttpRequest();
  } else if (window.ActiveXObject) {
    XMLHttpRequestObject = new 
     ActiveXObject("Microsoft.XMLHTTP");
  }

  if(XMLHttpRequestObject) {
    XMLHttpRequestObject.open("POST", url); 
    XMLHttpRequestObject.setRequestHeader('Content-Type', 
      'application/x-www-form-urlencoded'); 

    XMLHttpRequestObject.onreadystatechange = function() 
    { 
      if (XMLHttpRequestObject.readyState == 4 && 
        XMLHttpRequestObject.status == 200) {
          callback(XMLHttpRequestObject.responseText); 
          delete XMLHttpRequestObject;
          XMLHttpRequestObject = null;
      } 
    }

    XMLHttpRequestObject.send(data); 
  }
}

function postDataReturnXml(url, data, callback)
{ 
  var XMLHttpRequestObject = false; 

  if (window.XMLHttpRequest) {
    XMLHttpRequestObject = new XMLHttpRequest();
  } else if (window.ActiveXObject) {
    XMLHttpRequestObject = new 
     ActiveXObject("Microsoft.XMLHTTP");
  }

  if(XMLHttpRequestObject) {
    XMLHttpRequestObject.open("POST", url); 
    XMLHttpRequestObject.setRequestHeader('Content-Type', 
      'application/x-www-form-urlencoded'); 

    XMLHttpRequestObject.onreadystatechange = function() 
    { 
      if (XMLHttpRequestObject.readyState == 4 && 
        XMLHttpRequestObject.status == 200) {
          callback(XMLHttpRequestObject.responseXML); 
          delete XMLHttpRequestObject;
          XMLHttpRequestObject = null;
      } 
    }

    XMLHttpRequestObject.send(data); 
  }
}

// register an event handler to an element
function setEvent( xmlNode, strName, strFunction ) {
  strName = strName.substr( 0, 2 ) == "on" ? strName.substr( 2, strName.length ) : strName;

  if( document.addEventListener ) {
    // w3c compatible style, not supported by internet explorer yet
    xmlNode.addEventListener( strName, new Function( "event", "event.preventDefault( ); " + strFunction ), true );
  } else if( document.attachEvent ) {
    // Internet Explorer    
    xmlNode.attachEvent( "on" + strName, new Function( "event", strFunction ) );
  } else {
    // old style (tag.onclick)    
    xmlNode[ "on" + strName ] = new Function( "event", strFunction );
  }
}

// hide an element
function hideElement( strID, blnUseDisplay ) {
  var xmlNode = document.getElementById( strID );
  if( xmlNode ) {
    blnUseDisplay ? xmlNode.style.display = "none" : xmlNode.style.visibility = "hidden"; 
  }
}

// makes an element visible
function showElement( strID, blnUseDisplay ) {
  var xmlNode = document.getElementById( strID );
  if( xmlNode ) {
    blnUseDisplay ? xmlNode.style.display = "block" : xmlNode.style.visibility = "visible";
  }
}