$(".no1" + jml).keyup(function () { //var msg = $("#msgbox"+jml).val(); var no1 = $(this).parents("#records").find("#no1").val(); //var cno = $(".no1"+jml).val(); //alert(no1); if (no1 < 3) { //$(this).parents("#records").find(".check_no").html(""); $("#msgbox").html("kosong"); } else { $.ajax({ type: "POST", url: "check_ajax.php", data: "no1=" + no1, success: function (html) { $("#msgbox").html(html); //My Questions if $("#msgbox1"), $("#msgbox2") he can run or display msgbox but $("#msgbox"+jml) or $(this).parents("#records").find("#msgbox").html(html); he dosnt work for me  } }); return false; } });