สคริปต์ บวก textbox ครับ พอดีผมไปได้สคริปต์มานะครับแต่ไม่เข้าใจเรื่องการ วนลูปน่ะครับ

<form name='form1' method=post target="" action="">
<script language="javascript">
function incomma(num){
	num = num.toString().replace(/\$|\,/g,'');
	if (isNaN(num)) num = "0";
	for (var i = 0; i < Math.floor(); i++)
	num = num.substring(0,num.length-(4*i+3))+','+num.substring(num.length-(4*i+3));
	return (num);
} 

function  chkmosalary()
{

		var aa1 = removecomma(document.form1.aa1.value) * 1;
		var aa2= removecomma(document.form1.aa2.value) * 1;	
		var aa3 = removecomma(document.form1.aa3.value) * 1;
		
		document.form1.tmh.value = aa1 + aa2 + aa3 ;
	}
</script>
	<script language="javascript">	
	function removecomma(in_fld) 
	{
	var t = 0;
	t = in_fld.length;
	var o_fld = "";
	var w_fld = "";
	for (var i=0;i<t;i++) {
	w_fld = in_fld.substring(i,i+1);
	if (w_fld != ",")
	o_fld = o_fld + w_fld; 
	}
	return (o_fld);
	}
</script>

<% 
for n=1 to 3
b="aa" & cstr(n)
%>
<p><%=n%><input type="text" name="<%=b%>" id="<%=b%>" size="3" onBlur="this.value=incomma(this.value);chkmosalary();" value="" style="text-align:right;"></p>


				<% 
					next										
						%>
						

<p>=<input type="text" NAME="tmh" id="tmh"  size="1" onBlur="this.value= incomma(this.value);" value="" readonly="">
</p>
</form>