DOM manipulation - Multiple forms - php

Question

I have several forms on my page (via a loop), each have it's own submit button.
I want to use AJAX to get and POST the data to a .php. I need to know which form was submitted so I can get the corresponding values.
It's a simple cart application. This form allows a user to change the quantity of the items in the cart before checkout.
You see that there are two "Change Quantity" buttons (sumbit buttons) and these two fields are wrapped in a form tag.
The loop that encloses the form is :
while ($row = $query->fetch_assoc()) {
$item_code = $row['product_id'];
$item_name = $row['name'];
$item_price = $row['price'];
$item_qty = $row['qty'];
print"<tr>
<td>
<img src='http://localhost/store/images/products/$item_code.jpg'>
</td>
<td>$item_code</td>1
<td>$item_name</td>
<td>$$item_price</td>
<td>
<form method='post' action='/store/processing/view_cart.php' class='cart_view_ajax' id='form_id_$item_code'>
<input type='text' maxlength='2' value='$item_qty' id='qty'>
<input type='hidden' value = '$item_code' name='product_id' id='product_id'>
<div><input type='submit' id='submit' value='Change Quantity'></div>
</form>
</td>
<td>x</td>
</tr>";
}
The Question :
How do I know via jQuery that which form was submitted? Help me out...
According the given answers, I've managed to get the Quantity of the submitted form like this by jQuery. Here's the code :
$('form.cart_view_ajax').on('submit', function(e) {
e.preventDefault();
// start working
var form = $(this);
var form_id = form.attr('id');
console.log($('#'+form_id).children().eq(0).val());
return false;
});

Answer 1

You can just use the 'product_id' because it should be unique to each item
<input type='hidden' value = '$item_code' name='product_id' id='product_id'>
Or you can add an unique ID property to the form tag
<form method='post' action='/store/processing/view_cart.php' class='cart_view_ajax' id='item_$item_code'>
$('form#item_3')
You can add an unique id to the row so can manipulate it later on and you can access the form later on.
<tr id="row_$item_code">
$('tr#row_3 form')
You can add 'data' attributes to the form
<form method='post' action='/store/processing/view_cart.php' class='cart_view_ajax' id='item_$item_code' data-form_id="$item_code">
var form_id = $('form#item_3').data('form_id');
Can we see the jQuery code you are currently using?

Answer 2

You may use another hidden input field that contains an identifier for that special form. I think that would be the easiest way to do it.