function load_center( filename, is_archive_extention, is_title ) {
window.scroll(0,0);
document.getElementById('center').innerHTML = '読み込み中です……';
filename = filename.replace( new RegExp( '(.*?.html).*', "i"), "$1" );
  try {
    xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
  } catch (e) {
    try {
      xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    } catch (e) {
      xmlhttp = false;
    }
  }
  if (!xmlhttp && typeof XMLHttpRequest!='undefined') {
    xmlhttp = new XMLHttpRequest();
  }

  if (xmlhttp) {
    xmlhttp.onreadystatechange = function() {
      if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
        var data = xmlhttp.responseText;
        data = data.replace( new RegExp( '\n', "g"), '' );
        data = data.replace( new RegExp( '\r', "g"), '' );
        data = data.replace( new RegExp( '.*<div id="center">(.*<div class="content-bottom"></div>)</div>.*', "i"), "$1" );
        document.getElementById('center').innerHTML = data;
        if ( is_archive_extention ) {
            cocolog_archive_extention();
        }
        if ( is_title ) {
            show_title();
            }
        }
    }
    xmlhttp.open('GET', filename);
    xmlhttp.send(null);
  }
}