function tb_xs(t,m,n){
for(var i=1;i<=m;i++){
if (i != n){
document.getElementById("tb"+t+ "_bt" + i).className= "ycbt";
document.getElementById("tb"+t+ "_nr" + i).className= "ycnr";}
else{
document.getElementById("tb"+t+ "_bt" + i).className= "xsbt";
document.getElementById("tb"+t+ "_nr" + i).className= "xsnr";}}}