function stylechange() {

	// initialize
	var pathname = window.location.pathname;
	var prefix = "";

	var dt = new Date;	// datetime object
	var h;                  // time count
	var flg = false;        // change flag
	var skin = "";          // skin dom object
	var rnd = Math.floor(Math.random()*1000);
	var day_rnd = rnd%2;

	// get stylesheet change time
	h = dt.getHours();
	if ( h > 16 || h < 7 ) {
		flg = true;
	}

	// get stylesheet link object by id
	skin = document.getElementById("skin");

	// change stylesheet
	if( flg ) {
			
		skin.href=prefix+"/shared/css/skin/skin03.css";
	}else{
		if(day_rnd==0){
			skin.href=prefix+"/shared/css/skin/skin01.css";
		}else{
			skin.href=prefix+"/shared/css/skin/skin02.css";
		}
	}
}
window.document.onLoad=stylechange();