var global_timer = 0;

function fnc_counter(){
	while(1){
		global_timer += 1;
		wait(-1);
	}
}

//or
var global_second;
function fnc_counter(){
	global_second = sys_seconds;
	while(1){
		if(sys_seconds != global_second){
			//do your function
		}
	}
}