谁能帮帮我，关于jsp页面计算并写入数据表的问题，新手。。跪求高手了。。。

请问一下，如图a1 a2 a3为查询数据库的值   文本输入框为需手动输入的值
a4的值为第一个文本框和a1的乘积，按提交按钮后a4的值写入一个新的数据表。能帮我实现一下吗，a4的值最好是文本框输完数字，马上就能计算出来，提交前最好有个页面确认一下。自己写了一些，高手有空帮我补充一下吧，谢谢各位了。。。
<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.sql.*" %>
<%@ page import="java.text.*"%>
<%@ page import="java.util.*"%>
<%@ include file="sgzbconn.jsp"%>

<HTML>
<HEAD><TITLE>test</TITLE>
<LINK href="sgzbimages/photo_system/style_china.css" type=text/css rel=stylesheet>
<META content="MSHTML 6.00.2800.1106" name=GENERATOR>
<style type="text/css">

</style>
</HEAD>
<BODY leftMargin=0
topMargin=0>
<TABLE height=92 cellSpacing=0 cellPadding=0 width=1000 align=center
background="sgzbimages/photo_system/blue.jpg" border=0>
  <TBODY>
  <TR>
      <TD> </TD>
</TR></TBODY></TABLE>
<%@ include file = "top.jsp" %>

<TABLE width=1000 height="297" border=0 align=center cellPadding=0 cellSpacing=0>
  <TBODY>
  <TR>
    <TD width=23> </TD>
    <TD width=744><LINK href="sgzbimages/photo_system/style_china.css"
      type=text/css rel=stylesheet>
  <form action="output_add.jsp" method="post" name="form1" id="form1" onSubmit="return form1check()" target="_top">
          <table width="900" border="0" align="center" bordercolor="#FFFFFF" bgcolor="#FFFFFF">
  <%!int a,b=2;%>
            <tr valign="baseline">
              <td colspan="5"> <div align="center"> </div></td>
            </tr>
            <tr>
              <td colspan="5"><div align="center"><strong>当班生产指标录入表 (录入前请认真核对！！！)</strong><%


String sqll="select  * from output_price order by id DESC LIMIT 1";
rs=stmt.executeQuery(sqll);
                             while(rs.next())

                            {

                            %></div></td>
            </tr>
            <tr>
              <td width="125"> </td>
              <td width="142"> </td>
              <td width="119"> </td>
              <td width="172"> </td>
              <td width="164"><span class="STYLE5"> 日期
<% String mDateTime1=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(Calendar.getInstance().getTime());
   out.println(mDateTime1);
   %>

              </span></td>
            </tr>
<tr>
   <td><span class="STYLE5">高炉煤气
            <input name="gas1" type="text" id="gas1" style="border:1px double rgb(187,185,185);font:9pt" value="0" size="8" maxlength="8" />
   X <%=rs.getString("gas1")%>a1</span></td>
   <td><span class="STYLE5">混合煤气
            <input name="gas2" type="text" id="gas2" style="border:1px double rgb(187,185,185);font:9pt" value="0" size="8" maxlength="8" />
            X <%=rs.getString("gas2")%>a2</span></td>
   <td><span class="STYLE5">精致煤气
            <input name="gas3" type="text" id="gas3" style="border:1px double rgb(187,185,185);font:9pt" value="0" size="8" maxlength="8" />
   X<%=rs.getString("gas3")%>a3</span></td>
   <td><span class="STYLE5"></span></td>
   <td>总计：a4 sun</td>
    </tr>
<tr>
   <td colspan="5">_____________________________________________________________________________________________________________________________________________________</td>
    </tr>
            <tr>
              <td><div align="center"></div></td>
              <td><div align="center">
                <input type="submit" name="Submit" value="提交" class="button">
              </div></td>
              <td colspan="3"><div align="center">
                <input type="reset" name="Submit2" value="重置" class="button">
              </div>                <div align="center"></div>              <div align="center"></div></td>
            </tr>
          </table>
        </form>
      </TD>
<TD width=11> </TD></TR></TBODY></TABLE>
<%@ include file = "down.jsp" %>
</BODY></HTML> jsp 数据库数据 --------------------编程问答-------------------- 请帮帮我吧，谢谢了 --------------------编程问答-------------------- 可以在a1上添加一个鼠标移开事件，事件中计算第一框和a1的乘积，然后把结果放到动态添加到a4中；
然后用弹窗来决定是否提交，如果信息不对，就点击否，不提交；
例如这样的形式

top.Dialog.confirm("是否确认修改？",function(){

			$.post(

				"updatebusiness.action",

				{"id":id,"productName":productName,"price":price,"pricenum":pricenum,"number":number,"unit":unit,"paymethod":paymethod,"fahuotime":fahuotime,"companyname":companyname,"fhrname":fhrname,"fhrtel":fhrtel,"fhrphone":fhrphone,"fhraddress":fhraddress,"shrname":shrname,"shrtel":shrtel,"shrphone":shrphone,"shraddress":shraddress,"zhongliang":zhongliang,"tiji":tiji,"baojia":baojia,"baoxianfei":baoxianfei,"baozhuang":baozhuang,"beizhu":beizhu,"songhuoren":songhuoren},

				function(data){

					if(data.ok){

						window.top.frmright.location.reload();

						top.Dialog.close();

					}else{

						top.Dialog.alert("系统出错，请重试！");

					}

				},

				"json"

			);

		});

--------------------编程问答-------------------- 可以在a1上添加一个鼠标移开事件，事件中计算第一框和a1的乘积，然后把结果放到动态添加到a4中；这处么弄，初学者。。能详细的点吗，谢谢 --------------------编程问答-------------------- <%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<script type="text/javascript">

  function autocount(){

  var AMOUN=document.getElementById('AMOUNT').value;

  var MONEY=document.getElementById('MONEY').value;

   document.getElementById('TOTAL_MONEY').value=AMOUN*MONEY;

  }

  </script>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />

<title>无标题文档</title>



</head>

<body>

<table width="1000" border="1">
  <tr>
    <td><input id="MONEY" name="MONEY" type="text" /></td>
  </tr>
  <tr>
    <td><input id="AMOUNT" name="AMOUNT" type="text" onblur='autocount()' /></td>
  </tr>
  <tr>
    <td><input id="TOTAL_MONEY" name="TOTAL_MONEY" type="text" readonly="ture" /></td>
  </tr>
</table>
</body>
</html>
能执行放到带数据库查询的网页就执行不了....

补充：Java ,  Web 开发