如何通过ajax从Django模板向视图发送值？

Question

I have a select box that calls a function on changes. The function finds the selected value from "Products" selectbox.
I want to throw that selected value to my views.py which after some operations return the list of data and Populates the Destination's selectbox.
I want to use ajax for this purpose. Please help.

My code looks like this:

<script type="text/javascript">
    function select_value()
    {
        var e = document.getElementById("Product");
        var prod = e.options[e.selectedIndex].text
        console.log(prod)
    }
</script>

This is what my selectbox look like:

<table>
    <tr>
        <td>
            <select id="Product" onChange="select_value();">
                {% for products in product_name_list %}
                    <option>{{products|safe}}</option>
                {% endfor %}
            </select>
        </td>
        <td>
            <select id="dest">
                {% for des in destinations_name_list %}
                    <option>{{des|safe}}</option>
                {% endfor %}
            </select>
        </td>
     </tr>
</table>

This is my views.py:

def selection_filter(request,prod):
    destination_objs = Destination.objects.filter(product=prod)
    destination_name = destination_objs.values_list('name')
    destination_name_list = []
    for iter_name in destination_name:
        destination_name_list.append(iter_name[0].encode('utf-8'))

    return render_to_response('temp/test.html',
                {"destination_name_list"    :   destination_name_list},
                )

Answer 1

I think the point you might be misunderstanding is that your Django template for your whole page will not be re-rendered "magically". In Django's standard model-view-template paradigm, the template is rendered just once, upon the initial request. The way you've written it, unless there's a default product selection, you're going to have an awkward empty <select> in the first render. But ignoring that...

For a problem like this, you need two views: one for rendering the whole page, and one for providing the Ajax response. There are two main options for the second view: 1) return JSON for interpretation/rendering by your script post-response or 2) return a fully rendered HTML fragment for direct insertion into your DOM. In this case, I'd just go for option 2.

I recommend looking into Jquery, as it makes Ajax and DOM manipulation super simple.

If you've got Jquery, it's as simple as adding to your script:

$.get('/destinations/' + prod)
.done(function (html) {
    $(#dest).html(html);
});

(You can do the same thing without Jquery too, but it requires a bit more wrangling)

Your test.html file should contain:

{% for des in destinations_name_list %}
    <option>{{des|safe}}</option>
{% endfor %}