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Browser and GUI Chrome

by Jakob Nielsenon January 30,2012

Summary:'Chrome' is the user interface overhead that surrounds user data and web page content.Although chrome obesity can eat half of the available pixels,一个合理的金额提高可用性。

What do we mean when talking about the "chrome" in a user interface manbetx官方网站手机版design?An attendee asked this question during a recent course onVisual manbetx官方网站手机版Design for Mobile and Tablet.Whenever someone asks us a basic question,I assume that many more people want the answer as well — and thus,this article on chrome.

  • Definition: Chrome is the visual manbetx官方网站手机版design elements that give users information about or commands to operate on the screen's content (as opposed to being part of that content).These manbetx官方网站手机版design elements are provided by the underlying system — whether it be an operating system,a website,or an application — and surround the user's data.
  • Not coincidentally,"Chrome" is also the name of Google's web browser,though I don't use the term in that sense here.

I don't know who came up with the term "chrome," but it was likely a visual analogy with the use of metal chrome on big American cars during the 1950s: the car body (where you sit) was surrounded by shiny chrome on the bumpers,tail fins,and the like.

Similarly,in most modern GUIs,the chrome lives around the edges of the screen,surrounding the middle area,which is dedicated to the user's data.

Chrome at Different System Levels

Following are some examples of chrome,which vary depending on the "underlying system":

  • On a Windows PC,the underlying system is the Windowsoperating system.In Windows 7,the chrome consists of theStartbutton,the task bar,the system tray,and the recycle bin.We might also consider the gadget area to be chrome,particularly if a user simply sticks to those gadgets that ship with the system.(As many do,due to user inertia and thepower of defaults.)
  • When usingapplication software,such as a word processor,the chrome is found in the menu bar,theribbonor toolbars,rulers,scrollbars,and various specialized panes,such as Word's thesaurus bar or Photoshop's palette of color swatches.
  • In aweb browser,the chrome includes the URL field,the browser toolbars,the browser buttons,the tabs,scrollbars,and status fields.
  • In amobile app,the chrome often includes a status bar across the top of the screen and a tab bar with command icons across the bottom.Sometimes,there's also a navigation bar below the status bar.
  • On awebsite,the chrome includes navigation bars,footers,logos,branding,the search box,and so forth.

Chrome Obesity: Don't Eat My Pixels

The penalty of chrome is clear:chrome takes up screen space,leaving less for the target content or data.This is particularly bad on mobile devices,where screen space is at an even higher premium than on tablets or PCs.But even on my 30-inch desktop monitor,the combined Windows and Excel chrome means that I can see only 67 rows of data in a spreadsheet instead of the 80 rows that would theoretically fit on the screen.Thus,without the chrome,I'd be able to review about 19% more data.

The spreadsheet example shows another downside of chrome: itaccumulatesas systems are nested within layers of other systems,each with its own chrome.Let's say,for example,that you use Facebook.Within a typical desktop browser window,the user's Facebook news feed accounts for only about 48% of the web page;Facebook's chrome and wasted screen space eat up the remaining 52%.(According to our definition,advertising isn't true chrome — because it's useless — but it's still overhead,so I'm counting it here.) When you further subtract the browser and OS chrome,theuser's news feed is allowed less than 40% of the screen space.

When Ianalyzed a range of website homepages9 years ago,I found that theactual content was allocated a paltry 20%of the user's screen.On today's bigger monitors,the relative overhead consumed by OS and browser chrome is less bloated,so the 40% allowed by Facebook is probably fairly representative of major websites.

Because cumulative chrome often eats more than half of our pixels,one guideline is certainly tobeware chrome obesity.

A second guideline is to consider ways oftemporarily hiding parts of the chromeand reveal it only when needed.Doing so is dangerous,however,because what's out of sight is often out of mind — and youdefinitely cannot rely on short-term memoryin user interface manbetx官方网站手机版design.Chrome that comes and goes works only if you:

  • Use asimple and reliableoperation to reveal the chrome (don't use gestures that are obtuse or subject to accidental activation).
  • Offer rock-solidconsistencyso that the hidden chrome's existence is drilled into the user's long-term memory through excessive repetition and the absence of any deviations or exceptions that would undermine learning.

Chrome's Benefits

Although expensive,chrome has considerable benefits:

  • Chromeempowers usersby providing a steady set of commands and options that are always visible (or at least easily revealed if my guidelines are followed).Chrome also stays in the same spot,解放用户不必定位它。Further,users are freed from the whims of particular web page or content manbetx官方网站手机版designers;that's one reason theBackbutton is one of the most popular features on the web.Chrome might be overhead in terms of screen pixels,but it's power at the user's fingertips that serves as an immediate escape hatch from obnoxious or useless web pages.
  • Chrome offers a set ofgeneric commandsthat work on all the different types of content and data that appear within its framework.Because it's always the same,users have less to learn,meaning that they can focus on their real-world needs rather than on the computer.
  • Chrome promotesconsistency and standards in the user interface,which facilitates learnability and makes users feel even more incontrol of their experiences.(Of course,this applies only if you follow the standard,rather thaninvent your own weird chrometo confuse users.)

On balance,chrome is good for usability.Just don't overdo it.