Why form is no valid?

Hi! I’m trying to add a new record with the form and ajax and now just valid form…
Form is here:

<form action="/NomSave/" method="post" id="nom-form">
 {% csrf_token %}
 <tr>
     <td class="pt-2 border"> {{ form.title}}</td>
     <td class="pt-2 border border-end-0" style="widht:400px;" >{{form.izm}}</td>
     <td class="text-start border border-start-0 pt-2 ml-2 " style="padding-left:0;"><button type="button" class="btn btn-secondary btn-sm  addbtn" data-bs-toggle="modal" data-bs-target="#exampleModal">+</button></td>
     <td class="pt-2 border border-end-0" style="widht:400px;" >{{form.category}}</td>
     <td class="text-start border border-start-0 pt-2 ml-2 " style="padding-left:0;"><button type="button" class="btn btn-secondary btn-sm  addbtn" data-bs-toggle="modal" data-bs-target="#exampleModal">+</button></td>
     <td class="pt-2 border " style="widht:80px;" >{{form.srok}}</td>
     <td class="pt-2 text-center" style="widht:100px;"> <button type="submit" class="btn  btn-primary btn-sm    addbtn " id="nomsavebtn" ><img class="img_btnsave" src="{% static '/images/check2.png' %}" title="Добавить/Сохранить" ></button></td>
 </tr>
</form>

view:

def NomSave(request):
    if request.method =='POST':
        form=NomForm(request.POST)
        
        if form.is_valid():
            print('Form is valid')
            return JsonResponse({'status':'Save'})
        else:
            print('Not valid form')
            return JsonResponse({'status':0})

ajax:

<script>
////////////////////////////////////////////Добавление строки Номенклатура/////////////////
$('#nom-form').on('submit',function(e){
event.preventDefault();
console.log('Кнопка добавить');
let csr=$("input[name=csrfmiddlewaretoken]").val();
let tlt=$('#idtitle').val();
let izm=$('#idizm').val();
let idc=$('#idcat').val();
let srk=$('#idsrok').val();

mydata={
csrfmiddlewaretoken:csr,
title:tlt,
izm:izm,
cat:idc,
srok:srk
}
console.log(mydata);
$.ajax({
url:'/NomSave/',
method:"POST",
data:mydata,
dataType:"json",
success:function(data){
if (data.status == 'Save'){console.log('Saved!')};
if (data.status == 0){alert('NO')};
}
});

});
////////////////////////////////////////Конец добавления строки/////////////////////////////
</script>

if remove JavaSrcipt code, form is valid! What wrong?
Thanks!

I found a bug!!

tmydata={
csrfmiddlewaretoken:csr,
title:tlt,
izm:izm,
cat:idc,
srok:srk
}

category:idc !!!