Custom Scrollbars in WebKit

Before each of the browser vendors we like was providing unique CSS controls, Internet Explorer was setting the tone.  One such example is IE's early implementation of CSS filters. Internet Explorer was also the first browser that allowed developers to, for better or worse, customize the display of scrollbars.  We had a laugh about scrollbar customization back then, but fast forward to today and WebKit allows us to customize the scrollbar with CSS too.  Let's have a look!

There are a variety of scrollbar properties to choose from, all which must be -webkit prefixed:

• scrollbar
• scrollbar-button
• scrollbar-track
• scrollbar-track-piece
• scrollbar-thumb
• scrollbar-corner
• resizer

Even better is that there are a number of pseudo classes which can be used.  From the WebKit blog post:

:horizontal - The horizontal pseudo-class applies to any scrollbar pieces that have a horizontal orientation.

:vertical - The vertical pseudo-class applies to any scrollbar pieces that have a vertical orientation.

:decrement - The decrement pseudo-class applies to buttons and track pieces. It indicates whether or not the button or track piece will decrement the view's position when used (e.g., up on a vertical scrollbar, left on a horizontal scrollbar).

:increment - The increment pseudo-class applies to buttons and track pieces. It indicates whether or not a button or track piece will increment the view's position when used (e.g., down on a vertical scrollbar, right on a horizontal scrollbar).

:start - The start pseudo-class applies to buttons and track pieces. It indicates whether the object is placed before the thumb.

:end - The end pseudo-class applies to buttons and track pieces. It indicates whether the object is placed after the thumb.

:double-button - The double-button pseudo-class applies to buttons and track pieces. It is used to detect whether a button is part of a pair of buttons that are together at the same end of a scrollbar. For track pieces it indicates whether the track piece abuts a pair of buttons.

:single-button - The single-button pseudo-class applies to buttons and track pieces. It is used to detect whether a button is by itself at the end of a scrollbar. For track pieces it indicates whether the track piece abuts a singleton button.

:no-button - Applies to track pieces and indicates whether or not the track piece runs to the edge of the scrollbar, i.e., there is no button at that end of the track.

:corner-present - Applies to all scrollbar pieces and indicates whether or not a scrollbar corner is present.

:window-inactive - Applies to all scrollbar pieces and indicates whether or not the window containing the scrollbar is currently active. (In recent nightlies, this pseudo-class now applies to ::selection as well. We plan to extend it to work with any content and to propose it as a new standard pseudo-class.)

In addition the :enabled, :disabled, :hover and :active pseudo-classes also work with scrollbar pieces.

A simple example of a custom scrollbar implementation would be:

::-webkit-scrollbar {
	width: 12px;
}

::-webkit-scrollbar-track {
	background: none;
}

::-webkit-scrollbar-thumb {
	background: -webkit-linear-gradient(left, #547c90, #002640);
	border: 1px solid #333;
	box-shadow: inset 1px 0 0 rgba(255, 255, 255, 0.4);
}

Using CSS gradients with the scrollbar provides an excellent opportunity to class up the scrollbar -- just take a look at how CodePen uses them within their scrollbars. Note that some properties are limited; for example, opacity cannot be applied to scrollbar properties.

Customizing scrollbars is a bit of a conundrum.  On one hand, it can enrich and help brand a given site.  On the other hand, some may see it as a "cheap trick" or Busch League  effect.  What do you think?