How do I refresh a page without losing the content typed in a form?

Question

I am developing a web application using Python and Django, and at some point I need the page to be updated, but without losing the information that was typed in a form.

I tried to use the script below, but even updating the page, all information is reset.

<script>
  window.onbeforeunload = function() {
    localStorage.setItem("name", $('#id_cliente_form-nome_razao_social').val());
    localStorage.setItem("tipopessoa", $('input[name=cliente_form-tipo_pessoa]').val());
    // ...
};

window.onload = function() {

    var name = localStorage.getItem("name");
    var tipopessoa = localStorage.getItem("tipopessoa");
    if (name !== null) $('#id_cliente_form-nome_razao_social').val("name");
    if (tipopessoa !== null) $('input[name=cliente_form-tipo_pessoa]').val("tipopessoa");

    // ...
}
</script>

My file py views. is like this:

class AdicionarClienteView(AdicionarPessoaView):
    template_name = "cadastro/pessoa_add.html"

    def get_context_data(self, **kwargs):
        context = super(AdicionarClienteView, self).get_context_data(**kwargs)
        return context

    def get(self, request, *args, **kwargs):
        form = ClienteForm(prefix='cliente_form')
        return super(AdicionarClienteView, self).get(request, form, *args, **kwargs)

    def post(self, request, *args, **kwargs):
        form = ClienteForm(request.POST, request.FILES,
                           prefix='cliente_form', request=request)
        return super(AdicionarClienteView, self).post(request, form, *args, **kwargs)

And my file of template HTML like this:

<div class="col-sm-12" style="margin-top:15px;">
  <div class="form-group">
    <div class="form-line">
      <input type="radio" name="{{form.prefix}}-tipo_pessoa" id="fisica" value="PF" {% if form.tipo_pessoa.value == 'PF' %}checked="checked"{% endif %}/>
      <label for="fisica"><strong>Pessoa Física</strong></label>
      <input type="radio" name="{{form.prefix}}-tipo_pessoa" id="juridica" value="PJ" {% if form.tipo_pessoa.value == 'PJ' %}checked="checked"{% endif %}/>
      <label for="juridica"><strong>Pessoa Jurídica</strong></label>
      <strong style="color:red;"> *</strong>
      {% if form.tipo_pessoa.errors %}<label class="error">{% for error in form.tipo_pessoa.errors %}{{error}}{% endfor %}</label>{% endif %}
    </div>
  </div>
</div>

<div class="col-sm-6">
  <div class="form-group">
    <div class="form-line">
      <label>{{form.nome_razao_social.label}}</label><strong style="color:red;"> *</strong>
      {% if form.nome_razao_social.errors %}<label class="error">{% for error in form.nome_razao_social.errors %}{{error}}{% endfor %}</label>{% endif %}
      {{form.nome_razao_social}}
    </div>
  </div>
</div>

// ...