//div层切换
function div_show(open_div,close_div,oClassName,cClassName){
		
		document.getElementById(open_div).style.display = "";
		document.getElementById(open_div+'_c').className = oClassName;
		
		var arr_div = close_div.split(',');
		for(var i=0;i<arr_div.length;i++){
			document.getElementById(arr_div[i]+'_c').className = cClassName;
			document.getElementById(arr_div[i]).style.display = "none";
		}
}