I can't get the sum of grandtotal in jquery

Question

How to get the grand total. Just like the link of the picture below, it only display the amount input and display it beside the other amount. How can I add the grand total.

this is the link of the picture. please click.

grandtotal = 0;
$('input[name^=amount]').each(function() {
    //alert($(this).val());
    grandtotal += $(this).val();
});
$("#grandtotal").html(grandtotal);

Answer 1

you're adding strings together, rather than numbers. If you want a number to display, you'll need to use:

//javascript
grandtotal += parseFloat($(this).val());

or, since you added [php] tag:

//php
grandtotal += floatval( $your_variable );