+ ajax_http_get(url,callback) now checks the HTTP response status and shows an
error message if the status is not OK (is not 200)
+ New function node(tag,attrs,children) to create document nodes with arbitraty
attributes and children. The functions node() and text() should now be enough
to construct arbitrary document trees in an easy, functional way, and many of
the more specialized functions could be removed.
+ When calling the function button(label,action,key), the action can be a
function instead of a string, so you can use local/anonymous functions.
+ New function debug(str) adds text to the element with id=debug, if it
exists.
Using AJAX instead of JSONP can give better caching in the browser, since the
URL doesn't need to contain a (dynamically generated) callback function name.
But because of the same origin policy in JavaScript, AJAX can only be used when
the HTML file is served from the same server as the PGF. The new function
http_get_json in support.js uses AJAX if this is the case, and falls back to
JSONP otherwise.
