gistfile1.txt

sizes = new Array({{ product_sizes|safe }});

function filterSizeSelectField()
{
    product_type = $("#id_product_type").val();
    fields = $("select[id*='-size']").serializeArray();
    size_options = '<option value="">---------</option>';
    $.each(sizes, 
	   function(i, size) 
	   {
	       if (size['product_type'] == product_type || size['product_type'] == null )
	       {
	           size_options += '<option value="' + size['id'] + '">' + size['name'] + '</option>';
	       }
	   })

    $("select[id*='-size']").html(size_options);
    $.each(fields, 
           function(i, field) 
           {
	       name = "#id_" + field.name
	       $(name).val(field.value);
	       if ($(name).val() == null)
	       {
	           $(name).val("")
	       }
           });
}

$("#id_product_type").change(filterSizeSelectField);
filterSizeSelectField();