Yii2-dynamicforms and javascript

Question

I have wbraganca dynamic forms working in Yii2, but I need to add a little function to multiply 2 fields and put value in a third, and do that in every new dynamic form (suppose field 1 is price, field 2 is amount and field 3 is total). With the code I have I'm able to do that but only on the first dynamic form.

<?php
$script = <<< JS
$('#itemsfactura-{$i}-cantidad').change(function(){
    var cantidad = $(this).val();
    var precio = $('#itemsfactura-{$i}-precio').val();
    $('#itemsfactura-{$i}-total_item').val(cantidad * precio);
});
JS;
$this->registerJs($script);
?>

This is the code for the dynamic form fields:

...
<div class="row">
    <div class="col-sm-4">
        <?= $form->field($modelItemFactura, "[{$i}]precio")->textInput(['maxlength' => true]) ?>
    </div>
    <div class="col-sm-4">
        <?= $form->field($modelItemFactura, "[{$i}]cantidad")->textInput(['maxlength' => true]) ?>
    </div>
    <div class="col-sm-4">
        <?= $form->field($modelItemFactura, "[{$i}]total_item")->textInput(['maxlength' => true]) ?>
    </div>
</div>...

Answer 1

Form

<div class="col-sm-4">
    <?= $form->field($modelItemFactura, "[{$i}]precio")->textInput(['maxlength' => true, 'onchange' => 'getProduct($(this))', 'onkeyup' => 'getProduct($(this))']) ?>
</div>
<div class="col-sm-4">
    <?= $form->field($modelItemFactura, "[{$i}]cantidad")->textInput(['maxlength' => true, 'onchange' => 'getProduct($(this))', 'onkeyup' => 'getProduct($(this))']) ?>
</div>

JS

function getProduct(item) {
    var index  = item.attr("id").replace(/[^0-9.]/g, "");
    var total = current = next = 0;

    var id = item.attr("id");
    var myString = id.split("-").pop();

    if(myString == "precio") {
        fetch = index.concat("-cantidad");
    } else {
        fetch = index.concat("-precio");
    }

    temp = $("#itemsfactura-"+fetch+"").val();

    if(!isNaN(temp) && temp.length != 0) {
        next = temp;
    }

    current = item.val();
    if(isNaN(current) || current.length == 0) {
        current = 0;
    }

    if(!isNaN(current) && !isNaN(next)) {
        total = parseInt(current) * parseInt(next);
    }

    totalItem = "itemsfactura-".concat(index).concat("-total_item");

    $("#"+totalItem+"").val(total);
}