Documented how to manually piece together URLs with get_script_name().

Thanks to timo and leovitch for the patch. Fixed #10328.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@13772 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/topics/http/urls.txt

@@ -926,3 +926,22 @@ permalink()
 The :func:`django.db.models.permalink` decorator is useful for writing short
 methods that return a full URL path. For example, a model's
 ``get_absolute_url()`` method. See :func:`django.db.models.permalink` for more.
+
+get_script_prefix()
+-------------------
+
+.. function:: get_script_prefix()
+
+.. versionadded:: 1.0
+
+Normally, you should always use :func:`~django.core.urlresolvers.reverse` or
+:func:`~django.db.models.permalink` to define URLs within your application.
+However, if your application constructs part of the URL hierarchy itself, you
+may occasionally need to generate URLs. In that case, you need to be able to
+find the base URL of the Django project within its web server
+(normally, :func:`~django.core.urlresolvers.reverse` takes care of this for 
+you). In that case, you can call ``get_script_prefix()``, which will return the
+script prefix portion of the URL for your Django project. If your Django
+project is at the root of its webserver, this is always ``"/"``, but it can be
+changed, for instance  by using ``django.root`` (see :ref:`How to use
+Django with Apache and mod_python <howto-deployment-modpython>`).