สอบถามเรื่องกดปุ่ม Enter หลังจากป้อนข้อมูลเสร็จแล้ว ช่วยดูให้หน่อยครับ

<?php $this->load->view('home');?>
	<div class="grid_10">
		<div class="box round first grid">
			<h2>บันทึกตัวเลข</h2>
				<div class="block">
					<div id="container">
				<ul>
					<li><a href="#tab-1"><span>3 ตัวบน</span></a></li>
					<li><a href="#tab-2"><span>3 ตัวล่าง</span></a></li>
					<li><a href="#tab-3"><span>2 ตัวบน</span></a></li>
					<li><a href="#tab-4"><span>2 ตัวล่าง</span></a></li>
				</ul>
			<div id="tab-1">
	<?php echo br();?>
<form name="frmMain" method="post">
<script language="JavaScript">
document.onkeydown = chkEvent 
	function chkEvent(e) {
		var keycode;
		if (window.event) keycode = window.event.keyCode; //*** for IE ***//
		else if (e) keycode = e.which; //*** for Firefox ***//
		if(keycode==13)
		{
			return false;
		}
	}
    function setNextFocus(objId,objId2){

        if (event.keyCode == 13 || event.keyCode == 40){  // Submit and Down
			if(objId=='button')
			{
				document.frmMain.submit();
			}
			else
			{
				var obj=document.getElementById(objId);
				if (obj){
					obj.focus();
				}
			}
        }
        if (event.keyCode == 38){  // Up
			if(objId2 != null)
			{
				var obj=document.getElementById(objId2);
				if (obj){
					obj.focus();
				}
			}
        }
}
function fncSum()
	{
		 if(isNaN(document.frmMain.num.value) || document.frmMain.num.value == "" || document.frmMain.num.value.length < 3)
		 {
			alert('(ตัวเลข)กรุณาตรวจสอบข้อมูลอีกครั้ง.');
			document.frmMain.num.focus();
			return;
		 }

		 if(isNaN(document.frmMain.total.value) || document.frmMain.total.value == "")
		 {
			alert('(จำนวนเงิน)กรุณาตรวจสอบข้อมูลอีกครั้ง.');
			document.frmMain.total.focus();
			return;
		 }

		 document.frmMain.txtNumberC.value = parseFloat(document.frmMain.num.value) + parseFloat(document.frmMain.total.value);
}

</script>                           
            <?php echo br('2');?>
			<label class="label">ตัวเลข</label>
            <input type="text" name="num" id="num" class="el08" maxlength="3" onkeydown="setNextFocus('total',null)">
            <?php echo br('2');?>
			<label class="label">จำนวนเงิน</label>
            <input type="text" name="total" class="el08" id="total" onkeydown="setNextFocus('submit','num')">
			<input type="hidden" name="idda" id="idda" value="1">
            <?php echo br('2');?>
			<div class="bk">
			<input type="button" id="save" value="บันทึก" onclick="fncSum();">
			<input type="button" id="cen" value="ล้างข้อมูล">
			</div>
<script type="text/javascript">
$(document).ready(function() {
$("#num").focus();
$("#show").hide();
$("#save").click(function(){
		$.post("<?php echo base_url()?>index.php/site/demo/data",
		{num:$("#num").val(),total:$("#total").val(),idda:$('#idda').val()}, 
		function(data){
		$("#show").show();
		$(".red").html(data);
	});  
});
$('#cen').click(function() {
                $("#num").val('');
                $("#total").val('');
                $.post("<?php echo base_url()?>index.php/site/demo/data",
                {num:$("#num").val(''),total:$("#total").val(''),idda:$('#idda').val('')}, 
		function(data){
                $("#show").hide();
				$(".red").html(data);
                $("#num").focus();
		});  
    });
});
</script>
			<div id="div1"></div>
			<?php echo form_close();?>
			<?php echo br();?>
			<div class="box round">
                            <div id="show">
				<div class="block">
						<div class="stat-col last">
						<span><h4>ตัวเลข / จำนวนเงิน</h4></span>
						<p class="red"><input type="text" name="txtNumberC" value=""></p>
						</div>
						<div class="clear">
					</div>
				</div>
              </div>
			</div>
			</div>	
			<div id="tab-2">
				please wait
			</div>
			<div id="tab-3">
				please wait
			</div>
			<div id="tab-4">
				please wait
			</div>
		</div>
<script type="text/javascript">
			$(document).ready(function () {
				$('#container').tabs({ fxSlide: true, fxFade: true, fxSpeed: 'normal'});
			});
		</script>
		</div>
	</div>
	<div class="clear"></div>
</div>
<?php $this->load->view('footer');?>