[whatwg] Specify href target with HTTP headers
whatwg.org at chsc.dk
Wed Mar 7 14:19:17 PST 2012
On <a> and <form> elements you can specify a target attribute, e.g.
_blank. But sometimes you don't know whether to open in _self or _blank
at the time the link is clicked/the form is submitted.
I suggest that a server can specify a link target in an HTTP header,
e.g. "Window-Target: _blank". The page would be equivalent to specifying
the same value in the <form> or <a> tag leading to the page. It should
probably be subject to some kind of restrictions, e.g. the header could
be ignored if the link destination and the referring page had different
origins, unless the referring page specified some special value in the
target, e.g. _server (this value would indicate that the link
destination is a somewhat trusted resource whose Window-Target header
should be honoured). This ensures that the referring origin is always in
control of the target.
It seems there was such a header (to some extent, at least) back in
The Content-Disposition: attachment/inline header does something related
not entirely. Its was originally invented for use in MIME mails.
Sometimes the form target cannot be determined until after the form has
been submitted. Assume you have a form of some kind. If the server-side
validation fails, you want to load the same page again (this time with
an error message) in the same window, but if the server-side validation
succeeds, you want to open a new window, e.g. containting a PDF or some
application-like window. This behaviour is sometimes done using
window.open() on the target page, but many popup blockers prevent this.
In Drupal 8 the administrative pages are opened in an overlay/lightbox
on top of the frontend pages. For each URL it is specified (by means of
wildcard patterns in hook_admin_paths()) whether it should open in the
overlay or in the entire browser window, i.e. whether the URL is an
administrative page or not. For each link on a page the target attribute
should be specified accordingly (this is handled client-side using a
click handler on <a> elements that matches the current href against the
wildcard patterns and dynamically alters the target attribute - see
Drupal.overlay.eventhandlerOverrideLink in ). Contrary to use-case #1
it /is/ possible to preprocess all links, but it is a lot of work for
all links on a page. It would be easier if the server could determine,
whether the link that was actually clicked on should open in the overlay
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