//getElementById
function el_id( id ) {
  return document.getElementById( id );

}


function changeInnerHtml( id, htmltext ) {
  if (id != undefined && htmltext != undefined && el_id( id )) {
    el_id( id ).innerHTML = htmltext;
  }

}


//XMLHttpRequest
var janus_xh;

var janus_script = 'get_content.php';


function createRequestObject( ) {
  var ro;
  var browser = navigator.appName;
  if (browser == "Microsoft Internet Explorer" ) {
    ro = new ActiveXObject( "Microsoft.XMLHTTP" );
  } else {
    ro = new XMLHttpRequest( );
  }
  return ro;

}


function janus_init( ) {
  janus_xh = createRequestObject( );
	if (!janus_xh) {
		//alert( "Ihr Browser wird nicht unterstuetzt" );
		return false;
	}
	return true;

}


function changeContent( id, value ) {
  if ( janus_xh != null && id != undefined && value != undefined) {
    janus_xh.open( 'GET', janus_script+'?value='+value, true );
    janus_xh.onreadystatechange = function( ) {
      if (janus_xh.readyState == 4) {
        var response = janus_xh.responseText;
        if (response != '') {
          changeInnerHtml( id, response );
          initLightbox( );
        }
      }
    };
    janus_xh.send( null );
  }

}