function dom(id){return document.getElementById(id);}


var cur_index=1;
var num=3; 
var settime;
function change_Menu(){
	
	for(var i=1;i<=num;i++){
		if(cur_index==i){
			dom("connect"+i).style.display ="block";
			dom("b"+i).className = "on"+i;
		}else{
			dom("connect"+i).style.display = "none";
			dom("b"+i).className ="out"+i;
		}
	}
}

function conAction(){
	if(cur_index<3){
	   cur_index++
	  }
	else{
	    cur_index=1
	  }
	change_Menu();
}

function startAction(){
	stopAction();
	settime=setInterval(conAction,700)
}

function stopAction(){
	clearInterval(settime);
}

function clickAction(num){
	stopAction();
	cur_index = num;
	change_Menu();
}