django request.is_ajax() workaround for IE

mimetype.py

def response_mimetype(request):
    tridentEngine = 'Trident' in request.META['HTTP_USER_AGENT'] or 'MSIE' in request.META['HTTP_USER_AGENT']	
    if tridentEngine:
        return 'text/html'
    else:
        return 'application/json'

template.html

<form action="?xhr=true" class="form" method="post">
...

views.py

if request.GET.get('xhr', False):
    return HttpResponse( retorno_forms, mimetype=response_mimetype(request))