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);
  }
}


function addEvent(elm,listener,fn){
try{
elm.addEventListener(listener,fn,false);
}catch(e){
elm.attachEvent("on"+listener,fn);
}
}

function External() {
    var externalLink = document.getElementsByTagName('a');
    for (var i = 0, len = externalLink.length; i < len; i++) {
        var a = externalLink[i];
        if (a.getAttribute('rel') == 'external') {
            a.onclick = function() {
                window.open(this.getAttribute('href'), '_blank');
                return false;
            }
        }
    }
}
addEvent(window,"load",External);


function PrintPage(){
	if(document.getElementById || document.layers){
		window.print();		//ˆó�ü‚ð‚µ‚Ü‚·
	}
}