Toggle Element State with Google Chrome and Mozilla Firefox
It's much easier to debug CSS than JavaScript since there are many fewer interactions in CSS, and they are much easier emulate. Still, element state debugging isn't simple...until now. Google Chrome's WebInspector and Mozilla Firefox's Firebug have a really sweet feature I just discovered which allows the developer to apply element states for the sake of debugging.
Chrome's WebInspector

The image above displays Chrome's "Toggle Element State" button, allowing developers to toggle CSS states via checkboxes.
Firefox's Firebug

The image displays Firebug's likewise menu, triggered by the down arrow on the CSS tab for an element.
This allows active CSS state bugging vs. simple CSS explorations to be much, much easier. Happy CSS debugging!
![fetch API]()
One of the worst kept secrets about AJAX on the web is that the underlying API for it, XMLHttpRequest, wasn't really made for what we've been using it for. We've done well to create elegant APIs around XHR but we know we can do better. Our effort to...
![Vibration API]()
Many of the new APIs provided to us by browser vendors are more targeted toward the mobile user than the desktop user. One of those simple APIs the Vibration API. The Vibration API allows developers to direct the device, using JavaScript, to vibrate in...
![MooTools Zebra Tables Plugin]()
Tabular data can oftentimes be boring, but it doesn't need to look that way! With a small MooTools class, I can make tabular data extremely easy to read by implementing "zebra" tables -- tables with alternating row background colors.
The CSS
The above CSS is extremely basic.
![Full Width Textareas]()
Working with textarea widths can be painful if you want the textarea to span 100% width. Why painful? Because if the textarea's containing element has padding, your "width:100%" textarea will likely stretch outside of the parent container -- a frustrating prospect to say the least. Luckily...
Great tip, thanks =)
FireBug does this for years. Just click the little arrow next to the style tab. It’s only
:hoverand:active, though.Awesome, just added that as well.
The only thing Chrome cant do with states is when I need to debug an element that matches selector
parentElement:hover element, for exampleChrome applies states only to selected element in inspector and when you selected another element, selected state is applied to new element
Next challenge: Debug pseudo elements with web inspector :p
the Chrome web inspector already supports pseudo elements.
Under the Matched CSS rules is a Psuedo element
I believe the latest version of firebug does similar, but I’m not sure as I haven’t used it in ages
Unfortunately you can not select the pseudo element like any other DOM-Element. Technically this is perfectly valid since pseudo-elements are not part of the DOM but I often miss that feature. Pseudo-elements are harder to debug than necessary.
Good stuff, from what I know this has been around for a while already.
@JAN BECK – not that hard really, you just have to select the main element and scroll down in the inspector panel to see the psuedo elements
it’s also possible to do this with Firefox’ built in developer tools :-)