Web Inspector and Firefox Dollar Functions

By  on  

Dollar Functions

Many of you probably didn't know this but WebKit-based like Safari and Chrome, in addition to Firefox, contain special dollar functions within the console object that allow you to grab elements within the current page.  While I've not determined the use of each method, a few of them are obvious:

// Dollar method
// Returns an element by ID
$ = function (id) {
	return document.getElementById.apply(document, arguments);
}

// Bling-Bling method
// Returns array of nodes found by QSA
$$ = function(selector) {
	return document.querySelectorAll.apply(document, arguments);
}

// Broke method
// returns the currently selected element within the console HTML pane
$0 = function toString() { [native code] }

The $1 - $4 methods are returning undefined, oddly enough.

Dollar Functions

It's not clear to me what the last few methods do.  Maybe they're placeholders for feature methods but they continue to be undefined for now.

Recent Features

  • By
    Welcome to My New Office

    My first professional web development was at a small print shop where I sat in a windowless cubical all day. I suffered that boxed in environment for almost five years before I was able to find a remote job where I worked from home. The first...

  • By
    Designing for Simplicity

    Before we get started, it's worth me spending a brief moment introducing myself to you. My name is Mark (or @integralist if Twitter happens to be your communication tool of choice) and I currently work for BBC News in London England as a principal engineer/tech...

Incredible Demos

  • By
    Create Your Own Dijit CSS Theme with LESS CSS

    The Dojo Toolkit seems to just get better and better.  One of the new additions in Dojo 1.6 was the use of LESS CSS to create Dijit themes.  The move to using LESS is a brilliant one because it makes creating your own Dijit theme...

  • By
    QuickBoxes for Dojo

    Adding to my mental portfolio is important to me. First came MooTools, then jQuery, and now Dojo. I speak often with Peter Higgins of Dojo fame and decided it was time to step into his world. I chose a simple but useful plugin...

Discussion

  1. Brian

    $0 returns whatever you have selected in the Elements tab.

    These all work in Firebug too, by the way.

  2. $0 and $1 return the currently selected DOM element and the previously selected DOM element, respectively. I haven’t yet found a use for this while debugging, mainly because selecting elements in the inspector and debugging in the console seem (for me at least) to be disconnected tasks, but maybe there will be a reason some day? ^_^

    Not sure about webkit’s inspector, but you can find the API for firebug’s CLI here: http://getfirebug.com/wiki/index.php/Command_Line_API

  3. Matthew F

    Perhaps if they plan to use it in the future, they have to reserve it now so that the dom-modifying frameworks don’t start using it :)

  4. Didn’t know about this, the bling-bling method is cool though, haha.

  5. farkob

    Now I get it, this is why Douglas Crockford says you shouldn’t use $ functions.

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!