var isClickTab = false;

function clickTab(id) {

	var obj;

	var tmp_id;

	for(i=1; i<=4; i++) {

		tmp_id = "tab_id" + i;

		obj = document.getElementById(tmp_id);

		obj.style.background = "url(images/tab_off.gif)";

	}

	tmp_id = "tab_id" + id;

	obj = document.getElementById(tmp_id);

	obj.style.background = "url(images/tab_on.gif)";



	obj = document.getElementById("tab_iframe");

	var url_id = "tab" + id + ".htm";

	obj.src = url_id;

}

function clickTabAuto(id) {

  if(isClickTab == false) {

    clickTab(id);

  }

}



setTimeout("clickTabAuto(2)",10000);

setTimeout("clickTabAuto(3)",15000);

setTimeout("clickTabAuto(4)",20000);

setTimeout("clickTabAuto(1)",25000);