count the values of a table column

[cleary1981]

Hi I have a table that I add rows to using javascript. I need to have a runnig total of one of the columns. Does anyone know how this can be done?

<table border="2" cellspacing="2" cellpadding="2" width=100% id="myTable1">
<tr>
<th> </th>
<th>Part no.</th>
<th>Description</th>
<th>Price (£)</th>
<th>Quantity</th>
<th>Discount</th>
<th>Supplier</th>
<th>Sub Total</th>
</tr>
</table>
<span>£<span id ="total"></span></span>

heres the javascript I use to add a row

var tbl = document.getElementById('myTable1');
    var lastRow = tbl.rows.length;
    // alert (lastRow);
    // if there's no header row in the table, then iteration = lastRow + 1
      var iteration = lastRow;
      var row = tbl.insertRow(lastRow);
 
      // cell number
      var cellLeft = row.insertCell(0);
      var textNode = document.createTextNode(iteration);
      cellLeft.appendChild(textNode);
 
      // part number
      var cellpno = row.insertCell(1);
      var t_pno = document.createTextNode(part_no);
      cellpno.appendChild(t_pno);
 
      //description
      var celldesc = row.insertCell(2);
      var t_desc = document.createTextNode(description);
      celldesc.appendChild(t_desc);
 
      //price
      var cellprice = row.insertCell(3);
      var t_price = document.createTextNode(price);
      cellprice.appendChild(t_price);
 
      //quantity
      var cellqty = row.insertCell(4);
      var t_qty = document.createTextNode(quantity);
      cellqty.appendChild(t_qty);
 
      //discount
      var celldisc = row.insertCell(5);
      var t_disc = document.createTextNode(discount);
      celldisc.appendChild(t_disc);
 
      //supplier
      var cellsup = row.insertCell(6);
      var t_sup = document.createTextNode(supplier);
      cellsup.appendChild(t_sup);
 
      //subtotal
      var cellsub = row.insertCell(7);
      var sub = quantity * price;
      var sub1 = (sub / 100) * discount;
      var sub2 = sub - sub1;
      var result = sub2.toFixed(2); 
      var t_sub = document.createTextNode(result);
      cellsub.appendChild(t_sub);
 
      document.getElementById('part_no').value = "";
      document.getElementById('quantity').value = "";
      document.getElementById('description').value = "";
      document.getElementById('price').value = "";
      document.getElementById('discount').value = "";
      total();

[Dormilich]

I'm not sure if you want to count rows or columns, nevertheless try following:

document.getElementById("mytable1").childNodes.length 
// should count tr elements (except when you use tbody)
document.getElementById("mytable1").firstChild.childNodes.length
// should count td elements of the first row

regards

[cleary1981]

Not sure what the first line is doing as it always gives a result of 1. The second line seems to count he number of rows. What I want to do is loop through each row and add the contents of a particular column to a variable. Any ideas?

[gits]

hi ...

try the following:

alert(document.getElementById("mytable1").childNodes[0].tagName);

i think this will tell you 'tbody' ... i guess you use IE? ... so you just need to add one step more and loop through the rows, then in every row though the coloumns and extract the value you need. for better advice it would be helpful to have something to work with ... so please post an example that you have so far.

kind regards

[cleary1981]

I havnt used tbody in my code. heres what I have so far

function total() {
    var tbl = document.getElementById('myTable1');
    var lastRow = tbl.rows.length;
    for (var i=1; i < lastRow; i++) {
        alert(tbl.rows[i].cols[7]);
    }
}

If I could just work out how to get the value of column7 for each row I would be sorted

[cleary1981]

ive worked it out

function total() {
    var tbl = document.getElementById('myTable1');
    var lastRow = tbl.rows.length;
    for (var i=1; i < lastRow; i++) {
        alert(tbl.rows[i].cells[7].innerHTML);
    }
}

[RamananKalirajan]

I havnt used tbody in my code. heres what I have so far

function total() {
    var tbl = document.getElementById('myTable1');
    var lastRow = tbl.rows.length;
    for (var i=1; i < lastRow; i++) {
        alert(tbl.rows[i].cols[7]);
    }
}

If I could just work out how to get the value of column7 for each row I would be sorted

[HTML]var table = document.getElementById("myTable1");
var lastRow = table.rows.length;
for (var i=1; i < lastRow; i++) {
alert(table.rows[i].cells[6].innerHTML);
}[/HTML]

This may help u out. In order to retrieve the seventh column i placed six in the cells.

Regards
Ramanan Kalirajan

[cleary1981]

Yeah had just worked that out. Thanks

The problem I am having now is that I am trying to add 2 values but it concatenates them instead. What can I do here?

function total() {
    var total =0;
    var tbl = document.getElementById('myTable1');
    var lastRow = tbl.rows.length;
    for (var i=1; i < lastRow; i++) {
        var val = tbl.rows[i].cells[7].innerHTML;
        var tt = total
        total = tt + val;
    }
    document.getElementById('total').innerHTML = total;
}

[cleary1981]

thats me sorted. I used parseFloat and that worked a treat. thanks guys

[Dormilich]

the + sign serves for mathematical addition as well as string concatenation. I think that you get concatenation because val (I think that's supposed to be a number) is retrieved by innerHTML (which is essentially a text node/node set) instead of value. You may try parseInt(), parseFloat() or Number() for conversion.

[gits]

I havnt used tbody in my code.

just a note: in IE that doesn't matter ... it always assumes a tbody ... have a look here (first comment) ... typically this problem is relevant for adding rows ... and in case you retrieve the firstChild of a table in IE it IS tbody ... even when you don't use it explicitly.

kind regards