Django form is not rendered properly after setting initial values dynamically

I am trying to render a form where some fields are initialized dynamically. The issue is the form is getting all the values assigned when I print the form, but those values does not show up when rendered.

My View is:

def zoneinfo(request):
    siteId = request.GET.get('siteId')
    form = PostForm(site = siteId.upper())
    print form
    return render(request, 'details.html', {'form': form})

details.html:

{% load staticfiles %}
<form action = "/zones/add" id="addNewZoneForm1" method='post'>{% csrf_token %}
<!-- <form  id="addNewSite" method='post'>{% csrf_token %} -->
    <fieldset>
        <table border="0" cellspacing="2" cellpadding="2" width="100%">
            {{ form.as_table }}
      <!-- Allow form submission with keyboard without duplicating the dialog button -->
      </table>
      <input type="submit" value="Submit">
    </fieldset>


</form>
<script type="text/javascript">
        function getSite(value){
        $.ajax({
             url: "sites/getinfo?siteId="+value,
             type: "get",
        })
    }
</script>

where Print form returns :

<tr><th><label for="id_site">Site:</label></th><td><select id="id_site" name="site" onChange="getSite(this.value);">
<option value="initialValue">----Select Site----</option>
<option value="abc">ABC</option>
<option value="xyz">XYZ</option>
</select></td></tr>
<tr><th><label for="id_city">City:</label></th><td><input id="id_city" maxlength="25" name="city" type="text" value="SAN" /></td></tr>
<tr><th><label for="id_address">Address:</label></th><td><input id="id_address" maxlength="25" name="address" type="text" value="SAN" /></td></tr>
<tr><th><label for="id_state">State:</label></th><td><input id="id_state" maxlength="50" name="state" type="text" value="SAN" /></td></tr>
<tr><th><label for="id_zip">Zip:</label></th><td><input id="id_zip" maxlength="10" name="zip" type="text" value="10000001" /></td></tr>
<tr><th><label for="id_description">Description:</label></th><td><textarea cols="40" id="id_description" name="description" rows="10">
</textarea></td></tr>

We can see in the html out put that the fields have values associated but they are not rendered in the view. There is no error that I am getting, just a form with empty fields

Thanks in advance for your help