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jQuery Cloning and incrementing input, textarea, that has name, id and for

I'm still very new to jQuery, and would need help to how to increment 3 elements in this code.
name, id & for.
The name consist of products[0]category, id consist of checkbox[0], for consist of checkbox[0] which is for labels on the checkbox that id use.
I've tried searching for examples. But all them haven't found any good results that i could learn from unfortunately. So in the codes below, they're not there to increase increment as i have totally no idea what else i can do to increase increment numbering.
$(document).ready(function() {
let $append = $('#append');
// append location's data listing
$append.on('change', '.location', function(){
var value = $(this).val();
$('.location_id').val($('#locations [value="'+value+'"]').data('locationid'));
$('.loc_desc').val($('#locations [value="'+value+'"]').data('locdesc'));
});
// enable checkbox for serialnumbers
$append.on('change','.enable-serial', function(){
let $item = $(this).closest('.product-item');
let $checkbox = $item.find('.enable');
$checkbox.prop('disabled', !this.checked);
});
// ctrl for key in checkbox
$append.on('click', '.keyin-ctrl', function() {
let $container = $(this).closest('.product-item');
let $serial = $container.find('.serial');
$container.find('.display').val(function(i, v) {
return v + $serial.val() + ';\n';
});
$serial.val('').focus();
});
// ctrl for del textarea
$append.on('click', '.undo-ctrl', function() {
let $container = $(this).closest('.product-item');
$container.find('.display').val('');
});
// clone product, increment products[x]var
$('#add_product').on('click', function() {
var itemNo = $('.product-item').length + 1;
var index = $('.product-item').length;
var regex = /^(.+?)(\d+)$/i;
let $product = $append.find('.product-item.template')
.clone()
.show()
.removeClass('template')
.insertAfter('.product-item:last');;
$product.find('span').text('#' + itemNo);
$product.find(':checkbox').prop('checked', false);
$product.find('.enable').prop('disabled', true);
$product.find('input, textarea').val('');
$('#append').append($product);
});
// delete product, but remain original template intact
$('#delete_product').on('click', function(){
var itemNo = $('.product-item').length + 1;
let $product = $append.find('.product-item:last:not(".template")');
$product.remove();
});
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<main class="shadow border">
<h4>{{ __('Product Details') }}</h4>
<hr>
<form method="post" action="">
<!-- Multiple Product addition -->
<div class="form-group row">
<label class="col-sm-2 col-form-label font-weight-bold">{{ __('Product Setting') }}</label><br/>
<div class="col-sm-5">
<button type="button" id="add_product" class="btn btn-dark">{{ __('Add Product') }} <i class="fas fa-plus-square"></i></button>
<button type="button" id="delete_product" class="btn btn-dark ml-3">{{ __('Delete Last Product') }} <i class="fas fa-minus-square"></i></button>
</div>
</div>
<hr>
<!-- Frist Group -->
<div class="product" id="append">
<!-- Product Details -->
<div class="product-item template">
<span>#1</span>
<div class="form-group row">
<label class="col-sm-2 col-form-label font-weight-bold">{{ __('Category') }}</label>
<div class="col-sm-2">
<input class="form-control" name="products[0]category" type="text" placeholder="eg. 333" maxlength="3"required>
</div>
<label class="col-sm-1 col-form-label font-weight-bold">{{ __('Code') }}</label>
<div class="col-sm-2">
<input class="form-control" name="products[0]code" type="text" placeholder="eg. 22" maxlength="2" required>
</div>
<label class="col-sm-1 col-form-label font-weight-bold">{{ __('Partnumber') }}</label>
<div class="col-sm-2">
<input class="form-control" name="products[0]partnumber" type="text" placeholder="eg. NGH92838" required>
</div>
</div>
<div class="form-group row">
<label class="col-sm-2 col-form-label font-weight-bold">{{ __('Brand') }}</label>
<div class="col-sm-2">
<input class="form-control" name="products[0]brand" type="text" placeholder="eg. Rototype" required>
</div>
<label class="col-sm-1 col-form-label font-weight-bold">{{ __('Quantities') }}</label>
<div class="col-sm-2">
<input class="form-control" name="products[0]qty" type="number" placeholder="eg. 1" required>
</div>
<label class="col-sm-1 col-form-label font-weight-bold">{{ __("Location") }}</label>
<div class="col-sm-2">
<input class="form-control location" type="text" name="products[0]loc_name" list="locations" value="">
<input type="hidden" class="location_id" name="products[0]location_id" value="">
<input type="hidden" class="loc_desc" name="products[0]loc_desc" value="">
</div>
</div>
<div class="form-group row">
<label class="col-sm-2 col-form-label font-weight-bold">{{ __("Description") }}</label>
<div class="col-sm-8">
<input class="form-control" name="products[0]description" type="text" placeholder="eg. Spare part for CSD2002">
</div>
</div>
<div class="form-group row">
<label class="col-sm-2 col-form-label font-weight-bold">{{ __('Seial Number(s)') }}</label>
<div class="col-sm-5">
<input class="form-control enable serial" maxlength="25" placeholder="Key in Serial Number and hit button 'Key In'" disabled>
</div>
<div class="col-sm-5">
<button class="btn btn-dark enable keyin-ctrl" type="button" disabled>{{ __('Key In') }}</button>
<button class="btn btn-dark enable undo-ctrl" type="button" disabled>{{ __('Del') }}</button>
<input class="form-check-input ml-4 mt-2 pointer enable-serial" id="checkbox[0]" type="checkbox">
<label class="form-check-label ml-5 pointer" for="checkbox[0]">{{ __('tick to enable serialnumber')}}</label>
</div>
</div>
<div class="form-group row">
<label class="col-sm-2 col-form-label"></label>
<div class="col-sm-5">
<textarea class="form-control display" name="products[0]serialnumbers" rows="5" style="resize: none;" placeholder="eg. SGH8484848" readonly></textarea>
</div>
</div>
<hr>
</div>
<!-- append start -->
</div>
<div class="form-group row">
<div class="col-sm-12 ">
#csrf
<button type="submit" class="btn btn-dark float-right ml-4">Next <i class="fas fa-caret-right"></i></button>
<!--<button type="button" class="btn btn-secondary float-right" onclick="history.back()">Previous</button>-->
</div>
</div>
<datalist id="locations">
#foreach($locations as $location)
<option value="{{ $location->loc_name}}" data-locationid="{{ $location->location_id }}" data-locdesc="{{ $location->loc_desc }}"></option>
#endforeach
</datalist>
</form>
</div>
</main>
So how do I actually achieve this to add increment to the NAME, ID and FOR my clones?
From the original template of products[0]variable to products[1]variable, checkbox[0] to checkbox[1]

If you want to increment either an ID, class, etc. you can't use .clone(), like the documentation warns:
Using .clone() has the side-effect of producing elements with
duplicate id attributes, which are supposed to be unique. Where
possible, it is recommended to avoid cloning elements with this
attribute or using class attributes as identifiers instead.
You'll have to do it "manually", following a very simple example below:
$( "#addrow" ).click(function() {
var count = $("#product").children().length;
$("#product").append("<input id='field[" + count + "]' type='text'>");
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div id="product">
</div>
<input id="addrow" type="button" value="Add field">

Calculate the total of item quantity into item price with dynamic HTML input fields using jQuery

I would like to calculate the total of item price multiple of item quantity using jQuery. I am using dynamic HTML input fields once I enter the amount it should calculate with quantity and give the total amount. please see the code below
My HTML Code
$(document).ready(function() {
var max_fields = 10; //maximum input boxes allowed
var wrapper = $(".add_new_field"); //Fields wrapper
var add_button = $(".add_another_product"); //Add button ID
var x = 1; //initlal text box count
$(add_button).click(function(e){ //on add input button click
e.preventDefault();
if(x < max_fields){ //max input box allowed
x++; //text box increment
$(wrapper).append('<div class="add_new_field"><div class="row"><div class="col-md-4"><div class="form-group"><label class="col-form-label"> Enter Product Name</label><input type="text" class="form-control" name="pname[]" placeholder="Product Name" tabindex="1"/></div></div><div class="col-md-4"><div class="form-group"><label class="col-form-label"> No. of Pieces</label><input type="text" class="form-control" name="pcount[]" placeholder="Product Inventory" tabindex="2" /></div></div><div class="col-md-3"><div class="form-group"><label class="col-form-label"> Estimated Amount</label><input type="text" class="form-control" name="estamount[]" placeholder="Product Inventory" tabindex="2" /></div><p>Amount: <span id="Amount"></span></p></div><i class="fa fa-remove"></i></div></div>'); //add input box
}
});
$(wrapper).on("click",".remove_field", function(e){ //user click on remove text
e.preventDefault(); $(this).parent('div').remove(); x--;
})
});
$('#EstmTotal').blur(function() {
$('.add_new_field').each(function() {
$(this).find('#Amount').html($('#PCount(0)', this).val() * $('#EstmTotal(0)', this).val());
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="add_new_field">
<div class="row">
<div class="col-md-4">
<div class="form-group">
<label class="col-form-label"> Enter Product Name</label>
<input type="text" class="form-control" name="pname[]" id="PName" placeholder="Product Name" />
</div>
</div>
<div class="col-md-4">
<div class="form-group">
<label class="col-form-label"> No. of Pieces</label>
<input type="text" class="form-control" name="pcount[]" id="PCount" placeholder="No.Of Items" />
</div>
</div>
<div class="col-md-3">
<div class="form-group">
<label class="col-form-label"> Estimated Amount</label>
<input type="text" class="form-control" name="estamount[]" id="EstmTotal" placeholder="Estimated Amount of Each" />
</div>
<p>Amount: <span id="Amount"></span></p>
</div>
<!--<div class="col-md-1 removebtn"><i class="fa fa-remove"></i></div>-->
</div>
</div>
<button class="add_another_product">Add another Product <i class="fa fa-plus"></i></button>
please see the image for better understanding of the question
There is always an option to discuss

Full code here please try this. it will work according to your requirement.
<!DOCTYPE html>
<html>
<head>
<title>Demo</title>
<script
src="https://code.jquery.com/jquery-3.3.1.min.js"
></script>
<script type="text/javascript">
function calculate(id){ console.log(id);
// $('#EstmTotal').on('blur',function(){
$(id).parents('.add_new_field').each(function() {
var count = $(this).find("#PCount").val();
var amount = $(this).find("#EstmTotal").val();
$(this).find('#Amount').html(count*amount);
});
// });
}
$(document).ready(function(){
$(".add_another_product").on('click',function(){
var html = '<div class="add_new_field">';
html += '<div class="row">';
html += '<div class="col-md-4">';
html += '<div class="form-group">';
html += '<label class="col-form-label"> Enter Product Name</label>';
html += '<input type="text" class="form-control" name="pname[]" id="PName" placeholder="Product Name"/></div></div>';
html += '<div class="col-md-4"><divclass="form-group"><label class="col-form-label"> No. of Pieces</label>';
html += '<input type="text" class="form-control" name="pcount[]" id="PCount" placeholder="No.Of Items"/>';
html += '</div></div>';
html += '<div class="col-md-3">';
html += '<div class="form-group">';
html += '<label class="col-form-label"> Estimated Amount</label><input type="text" class="form-control" name="estamount[]" id="EstmTotal" placeholder="Estimated Amount of Each" onblur="calculate(EstmTotal)" />';
html += '</div><p>Amount: <span id="Amount"></span></p></div>';
html += '</div></div>';
$(this).before(html);
})
})
</script>
</head>
<body>
<div class="add_new_field">
<div class="row">
<div class="col-md-4">
<div class="form-group">
<label class="col-form-label"> Enter Product Name</label>
<input type="text" class="form-control" name="pname[]" id="PName" placeholder="Product Name"/>
</div>
</div>
<div class="col-md-4">
<div class="form-group">
<label class="col-form-label"> No. of Pieces</label>
<input type="text" class="form-control" name="pcount[]" id="PCount" placeholder="No.Of Items"/>
</div>
</div>
<div class="col-md-3">
<div class="form-group">
<label class="col-form-label"> Estimated Amount</label>
<input type="text" class="form-control" name="estamount[]" id="EstmTotal" onblur="calculate(EstmTotal)" placeholder="Estimated Amount of Each"/>
</div>
<p>Amount: <span id="Amount"></span></p>
</div>
<!--<div class="col-md-1 removebtn"><i class="fa fa-remove"></i></div>-->
</div>
</div>
<button class="add_another_product">Add another Product <i class="fa fa-plus"></i></button>
</body>
</html>

Do not use same id for multiple elements, user class instead of id. See below code to get amount
$(function(){
$(document).on("blur", "div.row .col-md-3 input[name='estamount[]']", function(){
var $row = $(this).closest('.row'); // get parent row
var est = $(this).val(); // read estimante
var count = $row.find('input[name="pcount[]"]').val(); // read count
$row.find('span.Amount').html(est*count); // put product
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="add_new_field">
<div class="row">
<div class="col-md-4">
<div class="form-group">
<label class="col-form-label"> Enter Product Name</label>
<input type="text" class="form-control" name="pname[]" placeholder="Product Name"/>
</div>
</div>
<div class="col-md-4">
<div class="form-group">
<label class="col-form-label"> No. of Pieces</label>
<input type="text" class="form-control" name="pcount[]" placeholder="No.Of Items"/>
</div>
</div>
<div class="col-md-3">
<div class="form-group">
<label class="col-form-label"> Estimated Amount</label>
<input type="text" class="form-control" name="estamount[]" placeholder="Estimated Amount of Each"/>
</div>
<p>Amount: <span class="Amount"></span></p>
</div>
<!--<div class="col-md-1 removebtn"><i class="fa fa-remove"></i></div>-->
</div>
</div>
<button class="add_another_product">Add another Product <i class="fa fa-plus"></i></button>

I have made following changes in your code, where in you are finding the first element inside the array. You will get the desired results
$('#EstmTotal').blur(function() {
$('.add_new_field').each(function() {
var elem = $($('#PCount')[0]).val();
var elem2 = $($('#EstmTotal')[0]).val();
$(this).find('#Amount').html(elem * elem2);
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="add_new_field">
<div class="row">
<div class="col-md-4">
<div class="form-group">
<label class="col-form-label"> Enter Product Name</label>
<input type="text" class="form-control" name="pname[]" id="PName" placeholder="Product Name" />
</div>
</div>
<div class="col-md-4">
<div class="form-group">
<label class="col-form-label"> No. of Pieces</label>
<input type="text" class="form-control" name="pcount[]" id="PCount" placeholder="No.Of Items" />
</div>
</div>
<div class="col-md-3">
<div class="form-group">
<label class="col-form-label"> Estimated Amount</label>
<input type="text" class="form-control" name="estamount[]" id="EstmTotal" placeholder="Estimated Amount of Each" />
</div>
<p>Amount: <span id="Amount"></span></p>
</div>
<!--<div class="col-md-1 removebtn"><i class="fa fa-remove"></i></div>-->
</div>
</div>
<button class="add_another_product">Add another Product <i class="fa fa-plus"></i></button>

$('#EstmTotal').blur(function(){
$('.add_new_field').each(function() {
$(this).find('#Amount').html($('#PCount').val()*$('#EstmTotal').val());
});
});
JsFiddle source

I changed your code a bit. Now it checks on the blur event of both elements and it checks if both have a value. If both have it sets the calculated value. If not the div will me emptied.
Also parsing the value to a floating point number. You can change this to integers if you prefer that. The typing checking to number will be same for integers. I round the number down to 2 decimals, mainly to get around floating point number precision issues.
Last, since i thought you will have the ability to create more rows dynamically I made the blur event delegated by your .add_new_field element. This assumes your
.add_new_field is a static element. If not change this to the closest static parent of your row. For this I also changed some id selectors to class selectors because id's need to be unique.
$('.add_new_field').on('blur', '.EstmTotal, .PCount', function() {
$(this).closest('.row').each(function() {
var pcCount = parseFloat($(this).find('.PCount', this).val());
var estTotal = parseFloat($(this).find('.EstmTotal', this).val());
if (typeof pcCount === 'number' && pcCount && typeof estTotal === 'number' && estTotal) {
var calculatedValue = pcCount * estTotal;
calculatedValue = Math.round(calculatedValue * 100) / 100;
$(this).find('.Amount').text(calculatedValue);
} else {
$(this).find('.Amount').text('');
}
});
});
$('.add_another_product').on('click', function(){
$('.add_new_field').append($('.row').first().clone());
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="add_new_field">
<div class="row">
<div class="col-md-4">
<div class="form-group">
<label class="col-form-label"> Enter Product Name</label>
<input type="text" class="form-control" name="pname[]" placeholder="Product Name" />
</div>
</div>
<div class="col-md-4">
<div class="form-group">
<label class="col-form-label"> No. of Pieces</label>
<input type="text" class="form-control PCount" name="pcount[]" placeholder="No.Of Items" />
</div>
</div>
<div class="col-md-3">
<div class="form-group">
<label class="col-form-label"> Estimated Amount</label>
<input type="text" class="form-control EstmTotal" name="estamount[]" placeholder="Estimated Amount of Each" />
</div>
<p>Amount: <span class="Amount"></span></p>
</div>
<!--<div class="col-md-1 removebtn"><i class="fa fa-remove"></i></div>-->
</div>
</div>
<button class="add_another_product">Add another Product <i class="fa fa-plus"></i></button>

Clean way to generate HTML

First of All I can't put all my elements in ONE ROW ONLY (all inline) I'm trying to generate one row of elements inside envVariablesDiv. I did all the html using javascript in my attempt and it's a huge mess and confusing.
Is there a simpler way to add rows of my elements everytime I click the button? I also need to be able to delete the row when I click delete.
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
<div class="top20 content-form">
<label class="col-sm-2 control-label" for="addEnv"><button class="btn btn-primary">add</button></label>
<div class="col-sm-10">
<label id="addEnv" class="label label-secondary pointer-label"><span class="fa fa-plus-circle"></span> Add environment variable</label>
<div id="envVariablesDiv">
<div class="input-group">
<span class="input-group-addon">Text</span>
<input id="msg" type="text" class="form-control" name="msg" placeholder="Additional Info">
</div>
<div class="input-group">
<span class="input-group-addon">Text</span>
<input id="msg" type="text" class="form-control" name="msg" placeholder="Additional Info">
</div>
<button class="btn btn-danger">Delete</button>
</div>
</div>
</div>
JS I done: The styling is different now. I want to use input group.
$('#addEnv').click(function () {
$('#envVariablesDiv').append('<div class="col-sm-5 top10"><label for="envName" class="control-label">Name</label><input id="envName" class="form-control" name="envName" type="text" placeholder="e.g. name1" /></div>' +
'<div class="col-sm-5 top10"><label for=envVar class="control-label">Variable</label><input class="form-control" id="envVar" type="text" name="envVar" placeholder="e.g. var1" /></div><div class="col-sm-2 top10"><button class="btn btn-danger"><span class="fa fa-trash"></span></button></div>');
});

Removing appended html code

I currently ran into a problem that i cannot remove the appended html with jQuery.
What works now is i can append the html that i want and it looks nice, but removing does not work. It works only on reload the first loaded html the others that i append are not working - I don't know why.
Here is my code for appending the html:
$("#adWasteStream").click(function(){
var newTxt = $('<div class="row-waste-container width-100"><div class="row"><div class="col-md-9"><p>Stream 1</p></div><div class="col-md-3"><button class="btn btn-add-waste deleteWasteStream"><i class="fa fa-minus-circle o-btn-add" aria-hidden="true"></i>Remove Waste Stream</button></div><div class="form-group col-md-7"><label for="business-mng-name" class="control-label">Waste Stream</label><input type="text" class="form-control form-input-field" name="business-mng-name" value="" required="" placeholder="Co-mingled recycling"><span class="help-block"></span></div></div><div class="row width-100"><div class="form-group col-md-4"><label for="business-mng-name" class="control-label">Volume (m <sup>3</sup>)</label><input type="text" class="form-control form-input-field" name="business-mng-name" value="" required="" placeholder="50"><span class="help-block"></span></div><div class="form-group col-md-4"><label for="business-mng-name" class="control-label">Weight (t)</label><input type="text" class="form-control form-input-field" name="business-mng-name" value="" required="" placeholder="20"><span class="help-block"></span></div><div class="form-group col-md-4"><label for="business-mng-name" class="control-label">Cost ($)</label><input type="text" class="form-control form-input-field" name="business-mng-name" value="" required="" placeholder="400"><span class="help-block"></span></div></div></div>');
$(".row-cont-main").append(newTxt);
});
My code for removing:
$(".deleteWasteStream").click(function(){
var curRow = $(this).parents('div.row-waste-container');
curRow.remove();
});
I don't need to use Id's as they need to be unique all elements (for back-end purposes).
The structure of the html looks like this:
<div class="row-waste-container width-100">
<div class="row">
<div class="col-md-9">
<p>Stream 1</p>
</div>
<div class="col-md-3">
<button class="btn btn-add-waste deleteWasteStream"><i class="fa fa-minus-circle o-btn-add" aria-hidden="true"></i>Remove Waste Stream</button>
</div>
<div class="form-group col-md-7">
<label for="business-mng-name" class="control-label">Waste Stream</label>
<input type="text" class="form-control form-input-field" name="business-mng-name" value="" required="" placeholder="Co-mingled recycling">
<span class="help-block"></span>
</div>
</div><!-- end row -->
<div class="row width-100">
<div class="form-group col-md-4">
<label for="business-mng-name" class="control-label">Volume (m <sup>3</sup>)</label>
<input type="text" class="form-control form-input-field" name="business-mng-name" value="" required="" placeholder="50">
<span class="help-block"></span>
</div>
<div class="form-group col-md-4">
<label for="business-mng-name" class="control-label">Weight (t)</label>
<input type="text" class="form-control form-input-field" name="business-mng-name" value="" required="" placeholder="20">
<span class="help-block"></span>
</div>
<div class="form-group col-md-4">
<label for="business-mng-name" class="control-label">Cost ($)</label>
<input type="text" class="form-control form-input-field" name="business-mng-name" value="" required="" placeholder="400">
<span class="help-block"></span>
</div>
</div><!-- end row -->
</div><!-- end row-waste container -->

You need to change your click event handler to handle also dynamically appended html.
Update your remove click handler with the code below
$("body").on('click' , '.deleteWasteStream' , function(){
var curRow = $(this).parents('div.row-waste-container');
curRow.remove();
});

You cant use .click() on dynamic objects/html. You can use .on()
$("body").on('click', '.deleteWasteStream', function( event ) {
var curRow = $(this).parents('div.row-waste-container');
curRow.remove();
});
Documentation: http://api.jquery.com/on/

Since the elements were created dynamically, they are not registered in DOM like pre-rendered elements (those rendered when your webpage is loaded in the browser). The best solution is binding the dynamically created element to the prerendered ones using the on event binder
$('.row-cont-main').on('click','.deleteWasteStream',function(){
var curRow = $(this).parents('div.row-waste-container');
curRow.remove();
});

How can I add some dynamic fields and use them to get some math results?

I'm using spring MVC and I have a form with dynamic field.
I can create several rows inside my form and each row has 4 input, like you can see below.
When I insert a number inside the second and third input field I want to multiply them and write the result into the fourth field.
How can I do it? Maybe using jQuery?
This is my code:
var riga = 0;
function aggiungiRiga() {
riga++;
var objTo = document.getElementById('rigaOfferta')
var divtest = document.createElement("div");
divtest.setAttribute("class", "removeclass" + riga);
var rdiv = 'removeclass' + riga;
divtest.innerHTML = '<div class="col-xs-5 col-sm-5 col-md-5"><div class="form-group"> <input type="text" class="form-control" id="descrizione_"' + riga + '" name="descrizione[]" value="" placeholder="Descrizione"></div></div><div class="col-xs-2 col-sm-2 col-md-2 col-md-offset-1"><div class="form-group"><input type="number" min="0" step="0.01" class="form-control" id="prezzo_"' + riga + '" name="prezzo[]" value="" placeholder="Prezzo €"/></div></div><div class="col-xs-2 col-sm-2 col-md-2 "><div class="form-group"><input type="number" min="0" step="0.5" class="form-control" id="ore_"' + riga + '" name="ore[]" value="" placeholder="Numero Ore"/></div></div><div class="col-xs-2 col-sm-2 col-md-2 "><div class="form-group"><div class="input-group"> <input type="text" class="form-control" id="totale_"' + riga + '" name="Totale[]" value="" placeholder="0" readonly="readonly"/><div class="input-group-btn"> <button class="btn btn-danger" type="button" onclick="rimuoviRiga(' + riga + ');"> <span class="glyphicon glyphicon-minus" aria-hidden="true"></span> </button></div></div></div></div>';
objTo.appendChild(divtest)
}
function rimuoviRiga(rid) {
$('.removeclass' + rid).remove();
}
<div id="rigaOfferta">
<jsp:text/>
</div>
<div class="col-xs-5 col-sm-5 col-md-5">
<div class="form-group">
<input type="text" class="form-control" id="descrizione_0" name="descrizione[]" value="" placeholder="Descrizione" required="required" />
</div>
</div>
<div class="col-xs-2 col-sm-2 col-md-2 col-md-offset-1">
<div class="form-group">
<input type="number" min="0" step="0.01" class="form-control" id="prezzo_0" name="prezzo[]" value="" placeholder="Prezzo €" required="required" />
</div>
</div>
<div class="col-xs-2 col-sm-2 col-md-2 ">
<div class="form-group">
<input type="number" min="0" step="0.5" class="form-control" id="ore_0" name="ore[]" value="" placeholder="Numero Ore" required="required" />
</div>
</div>
<div class="col-xs-2 col-sm-2 col-md-2 ">
<div class="form-group">
<div class="input-group">
<input type="text" class="form-control" id="totale_0" name="Totale[]" value="0" placeholder="0" readonly="readonly" />
<div class="input-group-btn">
<button class="btn btn-success" type="button" onclick="aggiungiRiga();"> <span class="glyphicon glyphicon-plus" aria-hidden="true"></span> </button>
</div>
</div>
</div>
</div>

Since you are going to have multiple input fields I suggest you add a class to them, something like input-listener and then a data attribute like data-row="n" where n stands for the row number. Then you add an event listener using jQuery (since it's easier) like so:
$('.input-listener').on('change', function(){
var row = $(this).data('row'); //this way you know which row you are working with
//now that you have the row you can get all the inputs you want
var prezzo = $('#prezzo_' + row).val() || 0;
var ore = $('#ore_' + row).val() || 0;
$('#totale_' + row).val(prezzo * ore);
});
As I didn't test the code I am not sure if it works 100% but it can be a place to start. If you find any errors in the code let me know and I'll try and correct them.
The only thing is that if you add a new row you will have to rebind this event handler, so you'll have to find a way around that. Maybe add it in your aggiungiRiga() function.
Edit: I removed the e and changed it to this then I added the # to the ID of the jQuery selectors as I previously forgot to.