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How to clone or create a nested DOM node and change all its containing id values according to a current id?

I need to display some numbers, strings from a class named Student, but i can't figure it out how i can change the id from children element. I have to use JavaScript.
what i tried to do:
class Student{
static count = 0;
constructor(nume, prenume, data_nasterii, foaie_matricola){
this.IdClasa = ++Student.count;
//definirea atributelor
this.nume = nume;
this.prenume = prenume;
this.data_nasterii = data_nasterii;
this.foaie_matricola = foaie_matricola;
}
afiseazaVarsta(){
}
afiseazaNotele(){
}
calculeazaMedia(){
}
adaugaNota(nota_noua){
}
}
var Stud = [new Student("Name", "Name1", "2000.01.01", "0123123"),
new Student("Green", "Blue", "2022/12.12", "321321")];
function afisareStudenti(){
let i = 0; let bol = false;
for(let x=1; x<=Student.count; x++) {
console.log(document.getElementById("AfisareStudenti"+x)==null);
if(document.getElementById("AfisareStudenti"+x)==null)
{
i = x;
bol = true;
break;
} else {
bol = false;
}
}
if((i<=Student.count)&&(bol==true)){
for(i; i<=Student.count; i++) {
console.log("i="+i);
var div = document.querySelector('#AfisareStudenti1');
var divClone = div.cloneNode(true);
console.log(divClone);
divClone.id = 'AfisareStudenti'+(i);
div.after(divClone);
var NumeStud = document.getElementById("NumeStudent"+(i-1));
var PrenumeStud = document.getElementById("PrenumeStudent"+(i-1));
var dataNastStud = document.getElementById("intData"+(i-1));
var FoaiaMatStud = document.getElementById("FoaiaMatStud"+(i-1));
NumeStud.id = "NumeStudent"+(i);
PrenumeStud.id = "PrenumeStud"+(i);
dataNastStud.id = "intData"+(i);
FoaiaMatStud.id = "FoaiaMatStud"+(i);
}
}
}
and this is the html file(the div that i want to clone):
<!--AFISARE-->
<div id="AfisareStudenti1">
<h2> Afisare Student 1</h2>
<label>Ce student doriti sa modificati? </label>
<form>
<label>Nume:</label><br>
<input type="text" id="NumeStudent1"><br>
<label>Prenume:</label><br>
<input type="text" id="PrenumeStudent1"><br>
<label>Data Nasterii:</label><br>
<input type="date" id="intData1"><br>
<label>Foaie matricola:</label><br>
<input type="text" id="FoaiaMatStud1"><br><br>
<input class="butoane" type="submit" value="Afisare"
onclick="afisareMeniuAfisStudenti()">
</form>
</div>
the class is saved in a dynamic array (could be n object of the class) so i have to make somehow to display the information dynamic. My version changes the id from all elements with the same id (every incrementation of i, the idnumber from id is incremented also). I tried to create that div with document.createElement but is impossible(at least for me) xD . I started coding in javascript 2 days ago, so please take it slow on me :(
I think i found the problem, but it doesn't solve it. (i need to put (i-1) when calling for getting the ids). (Newbie mistake)

Having commented ...
"I have the feeling that if provided with the broader picture the audience could be of much more help since the OP could be provided back with leaner/cleaner and better maintainable approaches."
... I nevertheless hereby lately provide a template-based approach which, besides supporting the OP's id based querying of student-items, is also easier to read and to maintain.
The code provided within the example-code's main function does not just implement the usage of the template-based node-creation via template literals and DOMParser.parseFromString but also prevents the default behavior of each student-form's submit-button by making use of event-delegation.
function createStudentElement(studentId) {
const markup =
`<div class="student-item" id="AfisareStudenti${ studentId }">
<h2> Afisare Student ${ studentId }</h2>
<label>Ce student doriti sa modificati? </label>
<form>
<label>Nume:</label><br>
<input type="text" id="NumeStudent${ studentId }"><br>
<label>Prenume:</label><br>
<input type="text" id="PrenumeStudent${ studentId }"><br>
<label>Data Nasterii:</label><br>
<input type="date" id="intData${ studentId }"><br>
<label>Foaie matricola:</label><br>
<input type="text" id="FoaiaMatStud${ studentId }"><br><br>
<input
class="butoane" type="submit" value="Afisare"
onclick="afisareMeniuAfisStudenti(${ studentId })"
>
</form>
</div>`;
const doc = (new DOMParser).parseFromString(markup, 'text/html');
return doc.body.removeChild(doc.body.firstElementChild);
}
// the button click handler.
function afisareMeniuAfisStudenti(studentId) {
console.log({ studentId })
}
function main() {
const itemsRoot = document.querySelector('.student-items');
// - prevent any form-submit by making use of event-delegation.
itemsRoot.addEventListener('submit', evt => evt.preventDefault());
// - just for demonstration purpose ...
// ... create student-items from a list of student IDs.
[1, 2, 3, 4, 5].forEach(studentId =>
itemsRoot.appendChild(
createStudentElement(studentId)
)
);
}
main();
.as-console-wrapper { left: auto!important; width: 50%; min-height: 100%; }
<div class="student-items"></div>

Tom's answer above is what you want for the element id problem that you asked about.
For your code in particular, you are going to have a couple other problems:
Because the final input is type="submit", its going to reload the page by default when it is clicked. The name of the "onclick" function also needs to match the function you defined (afisareStudenti).
You have:
<input class="butoane" type="submit" value="Afisare" onclick="afisareMeniuAfisStudenti()">
Change this to:
<input class="butoane" type="submit" value="Afisare" onclick="afisareStudenti(event)">
Now, when you click that button, it will call the afisareStudenti function and pass in the "event". So if you change:
function afisareStudenti(){
let i = 0; let bol = false;
to:
function afisareStudenti(event){
event.preventDefault()
let i = 0; let bol = false;
This will correctly call your function, and prevent the "default" action of that submit button from reloading the page.

To change the id attribute of children elements, you could use Element.querySelector() on divClone.
Because if you use Document.querySelector() or Document.getElementById() you will get the first element that matches your selector (i.e.children of div#AfisareStudenti1).
let i = 2;
var div = document.querySelector('#AfisareStudenti1');
var divClone = div.cloneNode(true);
divClone.id = 'AfisareStudenti'+(i);
divClone.querySelector("h2").innerText = "Afisare Student " + i;
var NumeStud = divClone.querySelector("#NumeStudent1");
var PrenumeStud = divClone.querySelector("#PrenumeStudent1");
var dataNastStud = divClone.querySelector("#intData1");
var FoaiaMatStud = divClone.querySelector("#FoaiaMatStud1");
NumeStud.id = "NumeStudent"+(i);
PrenumeStud.id = "PrenumeStud"+(i);
dataNastStud.id = "intData"+(i);
FoaiaMatStud.id = "FoaiaMatStud"+(i);
div.after(divClone);
<div id="AfisareStudenti1">
<h2> Afisare Student 1</h2>
<label>Ce student doriti sa modificati? </label>
<form>
<label>Nume:</label><br>
<input type="text" id="NumeStudent1" /><br>
<label>Prenume:</label><br>
<input type="text" id="PrenumeStudent1" /><br>
<label>Data Nasterii:</label><br>
<input type="date" id="intData1" /><br>
<label>Foaie matricola:</label><br>
<input type="text" id="FoaiaMatStud1" /><br><br>
<input class="butoane" type="submit" value="Afisare" onclick="afisareMeniuAfisStudenti()" />
</form>
</div>

How can I check if a variable is a specific type using javascript?

I'm a beginner in web development and I have an HTML form where a person can add his address , address number, region and postal code . In this form the address and the region have to contain only char letters .
(ex. Lakewood : correct Lakewood13 : error) . If any of these two variables contains a number I have to enter my data again to continue . Else, I move to the next page . I'm a complete beginner in javascript which I need to use to check my variable types and I would appreciate your help with guiding me to solve this problem .
This is my code with my HTML form with the address number and the region which are the variables we need in this problem :
function checkdata(){
//the two elements we need to check
var a = document.getElementById("address");
var r = document.getElementById("region");
if(typeof(a.value) === 'string'&&(typeof b.value) ==='string'){
//continue to next page(but how can I check if numbers are in the strings ?)
}
else{
//go back to form and enter again(how can I enter the elements again ? )
}
}
<div class = "form-area" id = "forma">
<form action="/action.page.html" class = "sign-form" >
<div class = "form-container">
<h1> Enter purchase data below : </h1>
<label for="addrs"> Address Name</label>
<input type = "text" placeholder = "Enter address name " id = "address" name = "addr" required/>
<label for="regn" > Region </label>
<input type = "text" placeholder = "Enter region " id = "region" name = "reg" required/>
</div>
<button type="submit" class="continuebtn" onclick = "checkdata()">Continue</button>
</form>
</div>
Thank you in advance .

You can try using regex to check if string contains any number in it:
if(!(/\d/.test(a.value)) && !(/\d/.test(b.value))){
Please Note: You also have to return false to prevent the default event if the condition is false and prefix return the function call in onclick attribute.
Demo:
function checkdata(){
//the two elements we need to check
var a = document.getElementById("address");
var r = document.getElementById("region");
if(!(/\d/.test(a.value)) && !(/\d/.test(r.value))){
alert('form submit');
}
else{
alert('no submit');
return false;
}
}
<div class = "form-area" id = "forma">
<form action="/action.page.html" class = "sign-form" >
<div class = "form-container">
<h1> Enter purchase data below : </h1>
<label for="addrs" Address Name</label>
<input type = "text" placeholder = "Enter address name " id = "address" name = "addr" required/>
<label for="regn" > Region </label>
<input type = "text" placeholder = "Enter region " id = "region" name = "reg" required/>
</div>
<button type="submit" class="continuebtn" onclick = "return checkdata()">Continue</button>
</form>
</div>

You can write a function for validity, then you can check for dependencies based on that **
function checkData() {
let adress = document.getElementById('address');
let region = document.getElementById('region');
function isValid(e) {
let isTrue;
for (let char in e) {
typeof e[char] !== 'string' ? alert('Please only type strings') : (isTrue = true);
}
return isTrue;
}
isValid(adress.value) && isValid(region.value) ? console.log('next page') : console.log('error');
}
checkData();
**

So need to check if the strings are containing numbers or not
hope you find more insight here: Check whether an input string contains a number in javascript
working demo :
// check if string contains number
function hasNumber(myString) {
return /\d/.test(myString);
}
function checkdata(e) {
e.preventDefault()
//the two elements we need to check
var a = document.getElementById("address");
var r = document.getElementById("region");
var isAddressContainsNumber = hasNumber(a.value);
var isRegionContainsNumber = hasNumber(r.value);
console.log(isAddressContainsNumber, isRegionContainsNumber)
if (isAddressContainsNumber === false && isRegionContainsNumber === false) {
console.log('None of string contains number')
} else {
console.log('One or Both string contains number')
}
}
const form = document.querySelector('.sign-form');
form.addEventListener('submit', checkdata);
<div class="form-area" id="forma">
<form class="sign-form">
<div class="form-container">
<h1> Enter purchase data below : </h1>
<label for "addrs" Address Name</label>
<input type="text" placeholder="Enter address name " id="address" name="addr" required/>
</label>
<label for "regn" > Region </label>
<input type="text" placeholder="Enter region " id="region" name="reg" required/>
</label>
</div>
<button type="submit" class="continuebtn">Continue</button>
</form>
</div>

I would recommend going through the string and getting the ASCII value of each character. Numbers 0-9 are ASCII characters 48-57. Javascript uses UTF-16 and the appropriate method (charCodeAt) returns a 16-bit UTF-16 value, but UTF-16 characters 0-127 match ASCII. So:
var testString = "abcd123";
var isValid = true;
for (var i=0;i<testString.length;i++)
{
if (testString.charCodeAt(i) > 47 && testString.charCodeAt(i) < 58)
{
isValid = false;
}
}
if (!isValid)
{
//Code here to alert the user
alert("There's a number in there!");
}

You are using typeof in wrong way, try this way
typeOf(variable you want to check)

Remove empty object from an array javascript

I'm using bootstrap validator to cloning the input and radio elements.
It is working fine, but i have issue while receiving these values as JavaScript array. Because i always have hidden input and radio elements in the DOM so it send empty object.
How i map my array object to receive values
var kids = $(".form--group").map(function() {
return {
kidName: $(this).find('.thevoornaam').val(),
newDob: $(this).find('.date_of_birth').val(),
}
}).get();
console.log(kids)
I'm receiving values like this..
[{kidName: "Test", newDob:"20"},{kidName: "", newDob:""} ]
Always receive second object with empty string.
How can remove the object from array if values are empty or undefined is..
I hope you guys understand my question.
Thanks in advance.

You can use filter to filter out the empty object like this
var kids = $(".form--group").map(function() {
return {
kidName: $(this).find('.thevoornaam').val(),
newDob: $(this).find('.date_of_birth').val(),
}
}).get();
kids = kids.filter(function (kid) {
return kid.kidName && kid.newDob;
});
console.log(kids)

If you want to exclude the item when every property is empty, undefined or 0;
let obj = [{kidName: "Test", newDob:"20"},{kidName: "", newDob:""} ];
let filtered = obj.filter(e=>{
for(let p in e){
if(e[p]){
return true;
}
}
});
console.log(filtered);

Check the strings before you create the objects:
$(document).ready(function(){
var kids = $(".form--group").map(function() {
var kidName = $(this).find('.thevoornaam').val();
var dob = $(this).find('.date_of_birth').val();
var result_arr = [];
if(kidName || dob)
{
var obj = {kidName: kidName, newDob: dob}
result_arr.push(obj);
}
return result_arr;
}).get();
console.log(kids)
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="form--group">
<input class="thevoornaam" value="Test Name" />
<input class="date_of_birth" value="Test Date" />
</div>
<div class="form--group">
<input class="thevoornaam" value="" />
<input class="date_of_birth" value="" />
</div>
<div class="form--group">
<input class="thevoornaam" value="Test Name" />
<input class="date_of_birth" value="Test Date" />
</div>

I want to make the input field has unique value

let us say that there is 5 input field for page (A)
<form class="classesName" action="action.php" method="POST">
<input type="text" name="class1" placeholder="Class Name1?" required="">
<input type="text" name="class2" placeholder="Class Name2?" required="">
<input type="text" name="class3" placeholder="Class Name3?" required="">
<input type="text" name="class4" placeholder="Class Name4?" required="">
<input type="text" name="class5" placeholder="Class Name5?" required="">
</form>
I want the user to fill all the fields BUT it must be unique class name for each field
so he can't fill
class a
class b
class a < this one is duplicated so it should display an error message
class c
class d
I think I can make if statement in the action.php page to check is there a duplication in the submitted field or not
but I don't want all the other values to be lost when I reload this page again to display the error for him
is there like a property in html5 or anything like that ?
thanks

No, this cannot be done with HTML5 alone. You'll have to write some JavaScript to make this happen. The JavaScript code should check all the values and if any two are identical prevent the form from submitting successfully.

In this case you could use javascript to validate the fields every time the user fills out a textbox. Here is an example:
$('input[type=text]').on('change',function(){
var arr = [];
$siblings = $(this).siblings();
$.each($siblings, function (i, key) {
arr.push($(key).val());
});
if ($.inArray($(this).val(), arr) !== -1)
{
alert("duplicate has been found");
}
});
JSFiddle: http://jsfiddle.net/x66j3qw3/

var frm = document.querySelector('form.classesName');
var inputs = frm.querySelectorAll('input[type=text]');
frm.addEventListener('submit', function(e) {
e.preventDefault();
var classArr = [];
for(var i = 0; i < inputs.length; i++) {
if(classArr.indexOf(inputs[i].value) != -1) {
inputs[i].style.backgroundColor = "red";
return false;
}
else
classArr.push(inputs[i].value);
}
frm.submit();
});
jsfiddle DEMO

why are names not being added to the list?

I found this fiddle and I am trying to get it to work...I can not figure out why the names are not being added to the list, for some reason Add button is acting like a submit button and I can not tell why...It should add all the numbers to a list so when I click submit, then it should send the numbers in an array..
JavaScript:
function bindName() {
var inputNames = document.getElementById("names").getElementsByTagName("inputNames");
for (i = 0; i < inputNames.length; i++) {
inputNames[i].onkeydown = function() {
if (this.value == "") {
setTimeout(deletename(this), 1000);
}
}
}
}
document.getElementById("addName").onclick = function() {
var num1 = document.getElementById("name");
var myRegEx = /^[0-9]{10}$/;
var myRegEx = /^[0-9]{10}$/;
var itemsToTest = num1.value;
if (myRegEx.test(itemsToTest)) {
var form1 = document.getElementById("names");
var nameOfnames = form1.getElementsByTagName("inputNames").length;
var newGuy1 = document.createElement("inputNames");
newGuy1.setAttribute("id", nameOfnames);
newGuy1.setAttribute("type", "text");
newGuy1.setAttribute("value", num1.value);
form1.appendChild(newGuy1);
num1.value = "";
bindName();
}
else {
alert('error');
}
};
HTML:
<h1>Enter Name</h1>
<div id="mainName">
<h2>name</h2>
<label for="name">Add Names: </label>
<input id="name" type="text">
<button id="addName">Add</button>
<form>
<div id="names">
</div>
<input METHOD="POST" action="text.php" type="submit" value="Submit">
</form>
</div>

I've seen
document.createElement("inputNames");
Shouldn't be
document.createElement("input");
?

Because this /^[0-9]{10}$/; will accept only 10 numbers and only that, try entering 1234567890 and you will see no error.

I'm not sure why your "name" field is restricted to 10 digit numbers, but I've got the thing to work.
http://jsfiddle.net/y8Uju/4/
I think the problem was that you were trying to create an element with the tag name inputNames, but that's not a valid tag. Instead I changed it to create inputs, and set the class to inputNames.