SourceURL support for scripts loaded by domManip using XHRs.

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This ticket is inspired by discussion in Chrome Developer Tools mailing group: ​https://groups.google.com/group/google-chrome-developer-tools/browse_thread/thread/e22f4cb5b0685dbd

SourceURL is a way to give a name to the script executed by eval() for debugging purposes. See ​http://blog.getfirebug.com/2009/08/11/give-your-eval-a-name-with-sourceurl/

Adding sourceURL to scripts loaded by domManip would make debugging easier. example: $('head').append('<script src="test.js'></script>');

Similar (but different) request ​http://bugs.jquery.com/ticket/8292 was closed as wontfix earlier, so some comments on the reasons mentioned there:

This is a functionality that:

• only developers will need while debugging

Yes, but is very valuable for developers and it comes with virtually zero cost for users.

• is only useful for Chrome users

sourceURL is supported by Firefox and WebKit (Chrome, Safari) which makes together more than 60% of browser market share.

• is of limited use as the names would need to be randomly generated

In the example mentioned above the url could and should be taken from the src attribute of the script tag. This is the same url the script was loaded from.

Vsevolod Vlasov, webkit reviewer

[dmethvin]

Worth investigating.

[jaubourg]

I'll look into it

[dmethvin]

Bulk change from enhancement to feature.

[dmethvin]

Ref ​https://github.com/jquery/jquery/pull/1099

[dmethvin]

Just a note after a quick look at that pull request. It's possible we might open up security holes by adding this if we're not careful with the sourceURL string and it has a newline. We also need to be alert for the IE conditional javascript bug, see #13274.

[m_gol]

As for the IE conditional compilation bug, fortunately that's behind us - the recent sourcemap specification changes also changed the //@ sourceURL= to //# sourceURL=.

[dmethvin]

If we switch to always using <script> tags for running code, we get this for free. I don't think the remaining use cases warrant a change to globalEval. See ​https://github.com/jquery/jquery/pull/1449 for tradeoffs.

[paul.irish]

This one just came up again: ​https://code.google.com/p/chromium/issues/detail?id=365645

I believe that with wither globalEval or a script tag the script will not have a real name that's debuggable in browser devtools. @sourceURL has strong x-browser support and would allow you to inject a filename for all injected scripts which would allow them to participate like real files.

[dmethvin]

See #14757, but since it's a feature I'll leave it open separately. I don't think we'd retain the globalEval method just so we could inject a #sourceURL comment, but if the user has added one the script tag method should use it.

[m_gol]

Migrated to ​https://github.com/jquery/jquery/issues/1733