function chTab(pre,cur,nex) {
	resetClass();
	if (cur == 'stb1') {
		document.getElementById(cur).className = 'stb_r';
		document.getElementById(nex).className = 'stb_sep';
	}
	else {
		document.getElementById(pre).className = 'stb_l';
		document.getElementById(cur).className = 'stb_r';
	}
}
function resetClass() {
	document.getElementById("stb1").className = 'stb_sep';
	document.getElementById("stb2").className = 'stb_sep';
	document.getElementById("stb3").className = 'stb_sep';
	document.getElementById("stb4").className = 'stb_sep';
	/*document.getElementById("stb5").className = 'stb_sep';
	document.getElementById("stb6").className = 'stb_sep';
	document.getElementById("stb7").className = 'stb_sep';
	document.getElementById("stb8").className = '';*/
}