Preserve URL hash when requesting via $.ajax

[mgol]

Originally reported by pferreir at: http://bugs.jquery.com/ticket/10495

While trying to inject the Facebook "like button" JS in a page in execution time, I got some funny behavior:

var fjs = $('script:first');
$('<script/>').attr({'async': true, 'src': '//connect.facebook.net/en_US/all.js#xfbml=1&appId=xxx'}).insertBefore(fjs)

fails (same with the equivalent before() call).

While

var fjs = $('script:first').get(0);
var e = $('<script/>').attr({'async': true, 'src': '//connect.facebook.net/en_US/all.js#xfbml=1&appId=xxx'}).get(0);
fjs.parentNode.insertBefore(e, fjs)

works just ok.

I tried different combinations of native/jQuery elements and they all fail. This happens at least since 1.6.1.

Issue reported for jQuery git

[mgol]

Comment author: pferreir

I forgot to add that in the first case the element seems to be added to the DOM only to be immediately removed.

[mgol]

Comment author: dmethvin

Why not use $.getScript ?  http://api.jquery.com/jQuery.getScript/

Can you provide a complete test case on jsfiddle.net? That would help us evaluate the problem.

[mgol]

Comment author: pferreir

Hello,

Here is a small example:  http://jsfiddle.net/RQVsa/

The uncommented code should work (show the "Like" button), while the commented on should fail. I tried $.getScript, with no success...

[mgol]

Comment author: timmywil

We filter out scripts in manipulation. getScript should be used, but we remove hashes from the url. I'm not sure why, but it's been there a while.

[mgol]

Comment author: dmethvin

Seems valid enough to keep open, until we figure out why we're removing the hash.

[mgol]

Comment author: dmethvin

Okay, this gives me an error from Facebook because of the xxx id:

 http://jsfiddle.net/RQVsa/10/

This gives the same error and doesn't have the hash as timmywil said:

 http://jsfiddle.net/RQVsa/11/

Since the script hasn't yet been executed the .insertBefore() is making the ajax request to request the script, but since the hash is stripped it's never going to see the correct id.

@jaubourg, do you know why we're stripping off the hash? Is there a specific reason for it, or just an omission?

[mgol]

Comment author: gibson042

A trip through the wayback machine reveals that we've been stripping hashes since 1.4.2's  fix for #4987.

I'd be in favor of preserving them, but if #3808 kills it for oldIE (and thus 1.9) then we may be unable to while maintaining API symmetry.

[dmethvin]

Hmmm. Now that we are attempting to parse the URL a bit more sanely per gh-1875 it might be possible to preserve the hash now.

[dmethvin]

By golly I think we can. After gh-1880 lands the hash is conveniently in ajaxLocation.hash and we could re-append it after adding any serialized params.

[gibson042]

This was unlocked by b091fdb, but we might want a distinct ticket for AJAX hash preservation.

[dmethvin]

Agreed, since it's potentially a breaking change it's a good 3.0 candidate.

[dmethvin]

Looking at the WHATWG XHR spec they have intentionally taken the hash (fragment) off the URL in the responseURL property. @jaubourg do you know why that might be, or who we might ask? In the OP's reported case it was a script tag but I am wondering if there is more to the reasoning for excluding it for XHR.

Edit: Additional info here seems to indicate stripping the fragment early is okay: https://lists.w3.org/Archives/Public/public-webapps-github/2015Jul/1046.html

[gibson042]

Fragments are never sent to servers, and are apparently not even exposed on fetches. But they can appear in the DOM and be visible to executing scripts. It's an extremely rare case to be sure, but one that script transports are technically wrong on as long as we strip them.

[modeckimellett]

Interesting. I asked a Stack Overflow question about this a while ago and never got a response. I'll add a link to this issue and the pull request to the question in comments. Thanks for working on this everyone!

For reference, my question is at http://stackoverflow.com/questions/32855458/jquery-ajax-content-from-an-end-point-which-responds-differently-depending-on-th