how to fetch values from array input in javascript

Question

How do I properly fetch values from array in javascript:

<html>
<head>
    <script type="text/javascript">
        function proc()
        {
            var cost = document.yoh.coz.value;
            var qtybuy = document.yoh.qbuys.value;
            var st = cost * qtybuy;

            var tbox = document.yoh.subtotal;
            if (tbox)
            {
                tbox.value = st;
            }
        }
    </script>
</head>
<body>

<?php
    include('conn.php');

    $prodname = $_GET['prodname'];
    $result = query_database("SELECT * FROM prod_table WHERE PRODUCT='$prodname'", "onstor", $link);
?>
<?php while ( $row = mysql_fetch_array($result) ) { ?>

<form name="yoh" method="get">
    Product id: <input type="text" name="prodid" value=""><br/>
    Cost: <input type="text" name="coz" value="<?php echo $row['S_PRICE']; ?>"><br/>
    Quantity to buy:<input type="text" name="qbuys" value="" onkeyup="proc();"></br>

    Subtotal:<input type="text" name="subtotal" value=""></br>
</form>

</body>
<?php } ?>
</html>

As you can see this program will just multiply the 2 values. One of the values would be fetched from the database, and the other comes from the user. If I do it this way, I don't get any results:

<html>
<head>
    <script type="text/javascript">
        function proc()
        {
            var cost = document.yoh.coz[].value;
            var qtybuy = document.yoh.qbuys[].value;
            var st = cost * qtybuy;

            var tbox = document.yoh.subtotal[];
            if (tbox)
            {
                tbox.value = st;
            }

        }
    </script>
</head>
<body>
<?php
    include('conn.php');

    $prodname = $_GET['prodname'];
    $result = query_database("SELECT * FROM prod_table WHERE PRODUCT='$prodname'", "onstor", $link);
?>
<?php while ( $row = mysql_fetch_array($result) ) { ?>

<form name="yoh" method="get">
    Product id: <input type="text" name="prodid[]" value=""><br/>
    Cost: <input type="text" name="coz[]" value="<?php echo $row['S_PRICE']; ?>"><br/>
    Quantity to buy:<input type="text" name="qbuys[]" value="" onkeyup="proc();"></br>

    Subtotal:<input type="text" name="subtotal[]" value=""></br>
</form>

</body>
<?php } ?>
</html>

Do I need to include the index manually? What do I need to do to achieve the same results when using arrays.

Zack Bloom · Accepted Answer · 2010-11-16 02:44:10Z

0

You need to iterate through the arrays. To iterate through an array (or object) in JavaScript:

for (key in arr){
    // The key will be set to each key in the array (arr)
    // The value at that key will be arr[key] (like always)
}

I'm not entirely sure what your goal is, but in general, know that the "[]" syntax is PHP only, JavaScript treats it as any other name (and possibly as a syntax error).

answered Nov 16, 2010 at 2:44

Zack Bloom

8,4372 gold badges22 silver badges27 bronze badges

That's not the recommended way to iterate arrays, since some libraries are known to add members to the array prototype. Use for (int i=0; i<arr.length; i++) arr[i]; instead.

rob
– rob

11/16/2010 02:46:26
Commented Nov 16, 2010 at 2:46

Add a comment |

Diodeus - James MacFarlane · Accepted Answer · 2010-11-16 02:45:46Z

0

You can use a name value:

cost=document.yoh.elements['coz[]'].value;

answered Nov 16, 2010 at 2:45

Diodeus - James MacFarlane

115k33 gold badges163 silver badges180 bronze badges

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