title: Auto complete Flask wtforms
body: <p>I want to auto-update my total amount field using quantity and item price? is there any way to do it using a flask without javascript? I want the total amount to be updated while typing quantity and item price.</p>
  <pre><code>class ItemForm(FlaskForm):
      item = StringField('Item')
      quantity=IntegerField('Quantity')
      item_price=IntegerField('Item Price')
      class Meta:
          csrf = False
  
  class CostumerForm(FlaskForm):
      costumer_name=StringField('Costumer Name: ')
      item_detail = FieldList(FormField(ItemForm), min_entries=1)
      add_item = SubmitField(label='Add Item')
      remove_item = SubmitField(label='Remove Item')
      total_amount=IntegerField('Total Amount')
      paid_amount=IntegerField('Paid Amount')
      submit=SubmitField('Submit')
      proceed=SubmitField('Proceed')
  
  @app.route('/costumer',methods=['GET','POST'])
  @login_required
  def costumer():
      form=CostumerForm()
      if form.add_item.data:
          form.item_detail.append_entry()
          return render_template('costumer.html', form=form)
      if form.remove_item.data:
          form.item_detail.pop_entry()
          return render_template('costumer.html', form=form)
      if form.validate_on_submit():
          item=breakdown(form.item_detail.data)[0]
          quantity=breakdown(form.item_detail.data)[1]
          item_price=breakdown(form.item_detail.data)[2]
          amount=breakdown(form.item_detail.data)[3]
          total_amount=breakdown(form.item_detail.data)[4]
          remaning_amount=total_amount-form.paid_amount.data
          sales=Costumer(admin_id=current_user.id,item_id=item,
                              costumer_name=form.costumer_name.data,quantity=quantity,
                              item_price=item_price,amount=amount,total_amount=total_amount,
                              paid_amount=form.paid_amount.data,remaning_amount=remaning_amount)
          db.session.add(sales)
          db.session.commit()
          return redirect(url_for('salesvoucher'))
      return render_template('costumer.html',form=form)
  
  costumer.html
  
  </code></pre>
   
          <br>
          <br> 
          <br>
          
              Sales
              
              
                  
                      {{form.hidden_tag()}}
                      
                          {{form.costumer_name.label}}{{form.costumer_name(class='form-control input-group-ig',placeholder='Costumer Name')}}
                      
                      
                      
                          
                              
                                  
                                  
                                    Item
                                    Quantity
                                    Item Price
                                  
                                  
                              
                              
                                  
                                      {% for field in form.item_detail %}
                                      
                                      {% for f in field%}
                                           {{ f(class='form-control') }}
                                      {% endfor %}
                                  
                                      {% endfor %}
                                 
                                
                      
                  
                      {{ form.add_item(class='btn btn-primary') }} {{ form.remove_item(class='btn btn-danger') }}
                      
                          {{form.proceed(class='btn btn-primary')}}
                      
              
                  
              
          
      
  ```