Bug 17907 – Inspector should support Firebug's magic $0 variable to access inspected node

• Component: Web Inspector (Deprecated)
• Status: RESOLVED FIXED

[Adam Roben (:aroben)]

Firebug has a magic $1 variable that's available from the Console to access the inspected node. We should support this variable in the Inspector's Console.

[Timothy Hatcher]

Thats a shame that Firebug uses $1. I was considering doing the gdb $n to refer to previous console results. More people might be familiar with Firebug's concept though.

[Adam Roben (:aroben)]

*** Bug 19390 has been marked as a duplicate of this bug. ***

[Anthony Ricaud]

$1 isn't available in Firebug 1.2b2. I don't know if it's a bug or if they abandoned it.

By the way, I've asked other web developers, nobody knew this shortcut.

Maybe you could agreed with Firebug developers on a more standard way to do this.

[Adam Roben (:aroben)]

<rdar://problem/6070208>

[Keishi Hattori]

According to this old documentation, I think $0 is the inspected node.
http://www.joehewitt.com/software/firebug/docs.php

[Keishi Hattori]

Created attachment 22794 [details]
not working patch

$0 seems to receive the appropriate object, but the security seems to block usage. For example, calling "$0" seems OK, but calling "$0.innerHTML" returns undefined. I tried doing wrapCallback on the node but that doesn't work either.

[Maciej Stachowiak]

Maybe this could have a less obscure name, like console.selectedNode or something. With autocomplete the typing is not a big deal and it is more memorable and less likely to conflict than $0.

[Adam Roben (:aroben)]

(In reply to comment #7)
> Maybe this could have a less obscure name, like console.selectedNode or
> something.

Putting it on the console object may not be ideal, since it's unlikely we want web pages to have access to this variable.

[Keishi Hattori]

Created attachment 33221 [details]
Implements $0, $1, $n

I've finally figured this out.

JSInspectorCallbackWrapper wraps the return value with JSInspectorCallbackWrapper::wrapOutgoingValue. It wraps it as a JSInspectorCallbackWrapper, which blocks getProperty, setProperty, deleteProperty, construct, hasInstance, and getPropertyNames.

I think this is overkill for objects from the "inspected window" but a necessary security measure for objects from the "inspector".

$0 - Variable containing the most recently inspected object .
$1 - Variable containing the next most recently inspected object .
$n(n) - Returns the nth most recently inspected object that has been inspected.

[Keishi Hattori]

Created attachment 33223 [details]
set history limit to 5

The history limit seems to be 5 in firebug.

[Timothy Hatcher]

Comment on attachment 33223 [details]
set history limit to 5

> +                profileEnd: function() { return console.profileEnd.apply(console, arguments) }, \
> +                 _inspectedNodes: [], \
> +                _addInspectedNode: function(node) { \

The indentation is one space off for _inspectedNodes.

+                      var _inspectedNodes = _inspectorCommandLineAPI._inspectedNodes; \

The local variable should not have an underscore prefix.

> +                $n: function(n) { return _inspectorCommandLineAPI._inspectedNodes[n] } \

Firebug really adds a $n function? Not just $0, $1, $2, $3 and $4?

[Joseph Pecoraro]

> Firebug really adds a $n function? Not just $0, $1, $2, $3 and $4?

Yah, documentation on this is rather hidden. Its at the bottom of Joe Hewitt's site:
http://joehewitt.com/software/firebug/docs.php

[Keishi Hattori]

Created attachment 33237 [details]
Syntax fixes

$n is pointless. It's only in their old outdated documentation anyway. (The assert* commands seems to have been deprecated) 

I vote to ditch it.

[Timothy Hatcher]

Lets ditch $n.

[Keishi Hattori]

Created attachment 33238 [details]
No more $n

[Adam Barth]

Committing to http://svn.webkit.org/repository/webkit/trunk ...
	M	WebCore/ChangeLog
	M	WebCore/inspector/front-end/Console.js
	M	WebCore/inspector/front-end/ElementsPanel.js
Committed r46338
	M	WebCore/ChangeLog
	M	WebCore/inspector/front-end/ElementsPanel.js
	M	WebCore/inspector/front-end/Console.js
r46338 = 4e1d680f3088d0cdd0b49c04acba4a47421cc311 (trunk)
No changes between current HEAD and refs/remotes/trunk
Resetting to the latest refs/remotes/trunk
http://trac.webkit.org/changeset/46338