Question

All i want to do in simple words: When input value is changed, i’ll put this value in db.
I want to add some ajax. I want to do this:
When I change my input value (focusout), i call some method, using get-parametr, my method looks like this:

def update_quantity
    @cart = current_cart
    @line_item = LineItem.find(params[:id])
    respond_to do |format|
      if @line_item.update_attribute(:quantity, params[:quantity]) #&& @cart.id == params[:cart]
        format.html { redirect_to(@line_item, :notice => 'Line item was successfully updated.') }
        format.xml  { head :ok }
      else
        format.html { render :action => "edit" }
        format.xml  { render :xml => @line_item.errors, :status => :unprocessable_entity }
      end
    end
  end

This is test-work, so it maybe have some bad solutions, and my view looks like this:

%p
    = line_item.art_name
    = line_item.ART_ID
    = line_item.art_code
    &times
    .cart-quantity
        = line_item.quantity        
        %input{ :class => "quantity", :value => line_item.quantity }
        = link_to "обновить", :controller => "line_items", :action => "update_quantity", :id => line_item.id, :quantity => line_item.quantity, :cart => @cart.id    
    = line_item.total_price

As you see, I want to: when input focus is out, i get new hidden link, and call it, which calls method, which is written upper.
What i need to do? what files to create and where, and how to do this? Wanna some ajax)

All i want to do in simple words: When input value is changed, i’ll put this value in db.

Answer 1

You don’t need a hidden link to accomplish this. Use the onblur field of the html element:

:javascript
  function updateQuantity() {
    $.ajax({
       url: "/line_items/update_quantity",
       type: "POST",
       data: {id: $(this).attr('id'), quantity: $(this).attr('quantity'), cart: $(this).attr('cart_id')} 
    })
  }

%input.quantity{:value => line_item.quantity, :onblur => updateQuantity(); :id => line_item.id, :quantity => line_item.quantity, :cart => @cart.id}

In this example I inlined the javascript, it should really go in your application.js document.ready() block

$(document).ready(function() {
  $(".quantity").onfocusout(function() {
     $.ajax({
           url: "/line_items/update_quantity",
           type: "POST",
           data: {id: $(this).attr('id'), quantity: $(this).attr('quantity'), cart: $(this).attr('cart_id')} 
        })
  })
})