// HTTP通信用、共通関数
function createXMLHttpRequest(cbFunc) {
    var XMLhttpObject = null;
    
    try {
        XMLhttpObject = new XMLHttpRequest();
    } catch(e) {
        try {
            XMLhttpObject = new ActiveXObject("Msxml2.XMLHTTP");
        } catch(e) {
            try {
                XMLhttpObject = new ActiveXObject("Microsoft.XMLHTTP");
            } catch(e) {
                return null;
            }
        }
    }
    
    if (XMLhttpObject) XMLhttpObject.onreadystatechange = cbFunc;
    return XMLhttpObject;
}


// ＩＤのコンテンツをセット
function $(id) {
	return document.getElementById(id);
}


// ページのトップへ戻る
function backToTop() {
  var x1 = x2 = x3 = 0;
  var y1 = y2 = y3 = 0;
  if (document.documentElement) {
      x1 = document.documentElement.scrollLeft || 0;
      y1 = document.documentElement.scrollTop || 0;
  }
  if (document.body) {
      x2 = document.body.scrollLeft || 0;
      y2 = document.body.scrollTop || 0;
  }
  x3 = window.scrollX || 0;
  y3 = window.scrollY || 0;
  var x = Math.max(x1, Math.max(x2, x3));
  var y = Math.max(y1, Math.max(y2, y3));
  window.scrollTo(Math.floor(x / 2), Math.floor(y / 2));
  if (x > 0 || y > 0) {
      window.setTimeout("backToTop()", 25);
  }
}


// メニューを閉じる
function hideMenu() {
    $("menu_about").style.display = "none";
    $("menu_service").style.display = "none";
    $("menu_cloud").style.display = "none";
    $("menu_column").style.display = "none";
}


// メニューを開く
function showMenu(menu) {
    hideMenu();
    $(menu).style.display = "block";
}