function hide_change(el, max){
	var td;
	var value = el.checked == true? "": "none";
	
	var list = document.getElementsByName("member_disp");
	var checks = 0;
	for(var i = 0 ; i < list.length; i++){
		if(list[i].checked)checks++;
		if(max < checks){
			el.checked = false;
			alert("これ以上同時に表示できません");
			return;
		}
	}
	
	for(var i = 0; i < 1000; i++){
		td = document.getElementById(el.value+"_"+i);
		if(td == undefined)break;
		td.style.display = value;
	}
	
}