On Thu, Dec 8, 2011 at 11:14 AM, BRIAN TINGLE
<[log in to unmask]> wrote:
> returning JSONP is the the cool hipster way to go (well, not hipster cool anymore, but the hipsters were doing it before it went mainstream), but I'm not convinced it is inherently a problem to return HTML for use in "AJAX" type development in a non--ironic-retro way.

Let me give you an example for why returning HTML is a difficult
approach, to say the least, when it comes to rich AJAX applications. I
had in my argument referred to a trend, connected to increasing
richness and interactivity in AJAX applications being developed today.

Say you have an <input> text component in your app. When its value
changes, a number of other components need to be updated. For
instance, a label (which is a <span>), and a button. In addition, it
may be the case that new elements appear on the page when that's the
case. For example, in our edition builder app, a user may change the
name of a proxy (as in EZProxy.) We need to update the title, we need
to update the label on the button where it can be removed, and we need
to update the status message when the configuration was last changed.
The response looks somewhat like this:

{"rs":[
  ["setAttr",["dP1Qvi","value","Off-Campus"]]
  ["setAttr",["dP1Q9m0","label","Delete Proxy Off-Campus"]],
  ["setAttr",["dP1Qy7","content","12:01:03 PM Dec 8, 2011 edition <a
target=\"_new\"
href=\"http:\/\/libx.org\/editions\/libxtestedition.php?edition=1C7B69E1.1\">1C7B69E1
rev 1<\/a> successfully saved. Click <a target=\"_new\"
href=\"http:\/\/libx.org\/editions\/libxtestedition.php?edition=1C7B69E1.1\">here<\/a>
to try out this configuration."]],
],"rid":11}

(simplified here.)

Coding this as a single HTML response is impossible. First of, it
would mean finding a common anchestor element that could be replaced,
which would result in a huge transfer. Obviously, you don't want
multiple AJAX requests. So you'd come up with your own encoding of all
updates to be done on the client. You could do that using multiple
HTML fragments, and defining your own response format around them.
Older frameworks have done that, but have since realized that it's
better to simply return JSON-encoded instructions to the client what
to update.

If we tell newbies (no offense meant by that term) that AJAX means
"send a request and then insert a chunk of HTML in your DOM," we're
short-changing their view of the type of Rich Internet Application
(RIA) AJAX today is equated with.

 - Godmar