function seltab(bpref, hpref, id_max, selected) {
	if (! document.getElementById) return;
	for (i = 0; i <= id_max; i++) {
		if (! document.getElementById(bpref + i)) continue;
		if (i == selected) {
			document.getElementById(bpref + i).style.visibility = "visible";
			document.getElementById(bpref + i).style.position = "";
			document.getElementById(hpref + i).className = "opened_tab";
		} else {
			document.getElementById(bpref + i).style.visibility = "hidden";
			document.getElementById(bpref + i).style.position = "absolute";
			document.getElementById(hpref + i).className = "closed_tab";
		}
	}
}