在JavaScript中计算总数

1 javascript

OP,请将此文本替换为您的问题的详细说明.您的代码如下.


我用过,document.getElementById但数学不起作用.我需要总计算:

<!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=iso-8859-1" />
<title></title>
<script type = "text/javascript">
function a()
{

var q = document.getElementById('ad').value;
document.getElementById('s').value=q  + q;
}

</script>
</head>
<?php 
$con = mysql_connect("localhost","root","");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("form1", $con);


error_reporting(E_ALL ^ E_NOTICE);
$nam=$_GET['msg'];

 $row=mysql_query("select * from inv where Name='$nam'");
while($row1=mysql_fetch_array($row))
{ 
$Name=$row1['Name'];
  $Address =$row1['Address'];
  $City=$row1['City'];
    $Pincode=$row1['Pincode'];
  $No=$row1['No'];
  $Date=$row1['Date'];
  $DCNo=$row1['DCNo'];
  $DcDate=$row1['DcDate'];
  $YourOrderNo=$row1['YourOrderNo'];
  $OrderDate=$row1['OrderDate'];
  $VendorCode=$row1['VendorCode'];
  $SNo=$row1['SNo'];
  $descofgoods=$row1['descofgoods'];
  $Qty=$row1['Qty'];
  $Rate=$row1['Rate'];
  $Amount=$row1['Amount'];
}

?>
<body>
<form id="form1" name="form1" method="post" action="">
  <table width="846" border="0">
    <tr>
      <td width="411" height="113">&nbsp;</td>
      <td width="412">&nbsp;</td>
    </tr>
  </table>
  <table width="846" border="0">
    <tr>
      <td height="38">&nbsp;</td>
    </tr>
  </table>
  <table width="846" border="0">

    <tr>
      <td width="390" rowspan="4">&nbsp;</td>
      <td width="92" height="35">&nbsp;</td>
      <td width="136"><?php echo $No;?></td>
      <td width="36">&nbsp;</td>
      <td width="170"><?php echo $Date;?></td>
    </tr>
    <tr>
      <td height="37">&nbsp;</td>
      <td><?php echo $DCNo;?></td>
      <td>&nbsp;</td>
      <td><?php echo $DcDate;?></td>
    </tr>
    <tr>
      <td height="34">&nbsp;</td>
      <td><?php echo $YourOrderNo;?></td>
      <td>&nbsp;</td>
      <td><?php echo $OrderDate;?></td>
    </tr>
    <tr>
      <td height="29">&nbsp;</td>
      <td><?php echo $VendorCode;?></td>
      <td>&nbsp;</td>
      <td>&nbsp;</td>
    </tr>
  </table>
  <table width="845" border="0">
    <tr>
      <td height="38">&nbsp;</td>
      <td>&nbsp;</td>
      <td>&nbsp;</td>
      <td>&nbsp;</td>
      <td>&nbsp;</td>
    </tr>
    <tr>
      <td width="34">&nbsp;</td>
      <td width="457">&nbsp;</td>
      <td width="104">&nbsp;</td>
      <td width="79">&nbsp;</td>
      <td width="149">&nbsp;</td>
    </tr>
      <?php $i=1;  
    $row=mysql_query("select * from inv where Name='$nam'");
while($row1=mysql_fetch_array($row))
{ 
$descofgoods=$row1['descofgoods'];
  $Qty=$row1['Qty'];
  $Rate=$row1['Rate'];
  $Amount=$row1['Amount'];
?>
            <tr>
              <td><?php echo $i;?></td>
              <td><?php echo $descofgoods;?></td>
              <td><?php echo $Qty;?></td>
              <td><?php echo $Rate;?></td>
              <td><input name="Amount" type = "text" id ="ad" value="<?php echo $Amount;?>" /></td>
            </tr>   


    <?php  $i++;} ?>
  </table>
  <table width="844" border="0">
    <tr>
      <td width="495" height="1065">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
        <input type="text" name="textfield2" />        &nbsp; &nbsp; &nbsp; &nbsp; </td>
      <td width="191">&nbsp;</td>
      <td width="144"><input type="text" name="tot" id="s" onclick="a()"; /></td>
    </tr>
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Dan*_*llo 6

您可能正在将字符串连接在一起,因此11从中获取1 + 1.尝试使用parseInt()将String转换为数字,如下所示:

var q = parseInt(document.getElementById('ad').value, 10);
document.getElementById('s').value = q + q;
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更新:正如CMS在另一个答案中指出的那样,您还生成具有相同ID的多个元素,这些元素无效,除此之外getElementById()只返回一个元素.查看CMS的答案,找出解决此问题的方法.

此外,请注意,如果要将十进制数加在一起,则无法parseInt()按上面的建议使用.您可以使用parseFloat()或一元运算+符将String转换为数字.不过你必须小心浮点运算.