python date jquery .change

$(document).ready(function(){
		var v = '{{ A }}';
		if (v)
			$('#A option[value*="'+v+'"]').attr('selected', 'selected');
		$('#A').change(function(){
			var t = $("#A option:selected").val();
			window.location.href = '{% url url %}'+'?limit_time='+t;
		});
	});	 


<select id='A' name="A">
				<option value="">所有</option>
				<option value="">近三個月</option>
				<option value="">三個月前</option>
			</select>


from datetime import date, timedelta
limit_time = request.GET.get('A')
if limit_time:
    now = date.today()
    t = now + timedelta(days=-90)
    if limit_time == u'':