I made a text input filed with jquery autocomplete where I query the users. So if I start typing the name of a user it shows the related users. It works fine but I like to avoid that if the user like not to choose from the pupped up list and possibly type all the name and it has a mistake. So I like to make a function that checks if the added value of the field is equals with any of the users in the database. How to do that?

html

<input type="text" class="form-control" placeholder="Type name here" name="kap_bar_01" id="kap_bar_01"> 

<script>
     $(function() {
        var names  =  [

          {% for u in related_users %}
            "{{ u.user.last_name }} {{ u.user.first_name }}",
          {% endfor %}
        ];

        $( "#kap_bar_01" ).autocomplete({
           source: names
        });
     });
  </script>

models.py

class Kapcsolodasok(models.Model):

    def __str__(self):
        return str(self.user_name)

    user_name = models.ForeignKey(User, on_delete=models.CASCADE, default=1)
    date = models.DateField(auto_now_add=True, auto_now=False, blank=True)
    kap_bar_01 = models.TextField(max_length=200)

views.py

def kapcsolodasok(request):

    profile = Profile.objects.get(user=request.user)
    related_users = Profile.objects.filter(projekt=profile.projekt)

    context = {
        'related_users': related_users,
        'profile': profile,
    }

    #lots of stuffs here

    return render(request, 'stressz/kapcsolodasok.html', context)

Thank you in advance!