With its widespread use and popularity, there have been criticisms of Mozilla Firefox. Some of these allegations towards Mozilla Firefox include:
- security, secure distribution, and a consolidated authoritative review for numerous new extensions
- a lack of some built-in ("out-of-the-box") features.
- refusal to implement non-standard web technologies;
- displaying a dialog box when a page is unavailable rather than showing an error page;
Firefox's extensive extension capability has prompted a boom in development of new add-on software. These extensions can address concerns requiring added functionality, as Firefox was designed (and is largely successful for) its streamlined interface and smaller size. Many if not most issues can be addressed by installing an extension, but there may be security concerns. The Firefox project was separated from the larger Mozilla Application Suite mainly to counter Mozilla's software bloat while providing a platform whereby each user could customize their browser based on an open platform for any number of new extensions.
General criticisms
Some frequently requested features have not been implemented. For example, the ability to resize the search bar through the user interface has been frequently requested but frequently turned down [1]. Some of these requests have been solved by someone creating an extension; for example, an extension to add a resize thumb to the search bar is available [2].
Firefox is sometimes slow to load pages when using the back and forward buttons. This is a result of issues with the coding in the Mozilla Suite, which was transferred over to Firefox. Currently, work in being done on resolving this issue [3].
The Firefox 1.0 release, in its attempt to implement Internet Explorer's behavior of requesting favicons, requests an icon file with every page view [4], despite the server's response that the file does not exist. The ramifications of this are that server administrators must either accept the unnecessary traffic increases, add a favicon.ico file under the root directory, or properly refer to a favicon image file within the page.
Criticisms from Internet Explorer users
When Firefox is unable to load a page (for example, when it cannot connect to the server), it displays an error dialog box instead of an error page, as used in Internet Explorer. This behaviour can be reversed, but the implementation is buggy. [5]
Firefox can take longer to launch than Internet Explorer. Internet Explorer's close ties to the operating system gives it the advantage of starting quickly once the program is launched - because Internet Explorer's code is loaded in memory on startup. Firefox can have a longer start time, typically if the user had just installed many extensions.
Standards noncompliance
Many Web sites have problems caused by careless development which causes the site to fail to comply with Web standards; sometimes the site is only tested in Internet Explorer and fails in other browsers such as Firefox. Users often blame the browser instead of the site developer when this happens. Common problems of this sort include misconfigured servers sending incorrect MIME types (so that, for instance, HTML documents are indicated as being plain text, which Firefox takes literally in accordance with the standards, but Internet Explorer second-guesses), invalid syntax in HTML, CSS, and JavaScript, and use of a nonstandard document object model (DOM) for scripting. While Firefox supports quite a bit of "bad code", it doesn't bend over backward quite as much in this regard as Internet Explorer, and to fully emulate Internet Explorer's behavior would require breaking some standards.
ActiveX
While not officially supported, it is possible to add support for ActiveX in Microsoft Windows using a plugin. [6]
There have been numerous security holes discovered in ActiveX in the past. In addition, there are relatively few public websites that require ActiveX; the most well-known site to use ActiveX is probably the Windows Update site. ActiveX is not portable to the wide variety of browser platforms in any case; non-x86 systems and systems based on Mac, Linux, or BSD typically cannot run ActiveX controls anyway. ActiveX is, however, quite common in corporate intranets and for web applications, which may hinder the adoption of Firefox on the corporate desktop.
Digital signatures and authenticity of downloads
Peter Torr, a program manager at Microsoft (who makes Firefox's primary competitor), wrote an essay "How can I trust Firefox?" on December 20, 2004. It began a firestorm of discussion on his own blogging forum, which included postings from notables like Peter da Silva [7]); a discussion on Slashdot [8] and a follow-up summary from Torr [9].
Torr pointed out that the many mirrors hosting Firefox downloads were often based on university (or even high school) campuses, and offered no guarantee that the installation files had not been tampered with. He also notes several flaws in Firefox's user interface.
Torr also incorrectly claimed in the original essay that there is no obvious way to disable plugins (such as Flash). Other points illustrated differences in security approach:
- Torr was disturbed that Firefox does not widely use digital signatures, since digital signatures are the basis of Internet Explorer's security approach. Peter da Silva and others countered that Internet Explorer's extreme dependence on digital signatures is a flaw - anyone can sign code simply by paying money. They cited Gator to demonstrate that many spyware programs are digitally signed. [10] [11] Digital signatures are not intended to show that code is benign or vulnerability-free; rather to prove the origin of the software. Even this is weak; in 2001 two Microsoft digital certificates were issued by Verisign to people who fraudulently claimed to represent Microsoft, and these certificates could have been easily used by malicious attackers to forge material "signed" by Microsoft. [12] Also, people can create companies and get certificates with arbitrary, misleading names, causing users to give unwarranted trust to signed programs. Instead of depending on digital signatures (especially since users rarely check who signed something), Firefox uses hash values and DNS to demonstrate the traceability of the Firefox software itself to a trusted site.
- Once installed, Firefox uses mobile code technologies that constantly limit code privileges while running, as opposed to Internet Explorer's ActiveX which is given uncontrolled access once it starts to run. Firefox proponents argue that Java and JavaScript are much more secure, because their privileges are constantly limited while running.
- Internet Explorer's security is dependent on "security zones"; Firefox proponents note that many attacks successfully confuse Internet Explorer's security zone implementation, and claim that Firefox's security is better in part because it does not depend on security zones.
Criticisms from Opera users
Opera has many features available without the installation of extensions. Firefox's philosophy is different, offering only core features by default to avoid possible bloat. Despite the Firefox team's efforts to offer as few things as possible, the executable size is still larger than that of Opera. However, the smaller program size in Opera may be the result of the binary compression of the executables using ASPack [13] [14].
Firefox does not have a cross-session browsing function, where pages displayed when the browser is exited are automatically reopened when the browser is restarted. At least one user who prefers cross-session browsing with Firefox either uses an extension such as Tabbrowser Extensions or Session Saver to produce equivalent results [15].
Accidentally-closed tabs cannot be reopened. Opera also offers a list of all closed tabs in a session, for quick restoration. Again, similar functionality is available for Firefox via extensions [16] [17].
Opera's interface is relatively more customizable, allowing toolbars, buttons and fields to be placed anywhere on the screen (or removed completely). Menus, keyboard shortcuts and mouse gestures may also be user-defined without needing to add extensions. Most extensions are hosted in the official Mozilla Update website, but Firefox's extensions are developed by third-parties.
While Firefox users can install their own search engines, they cannot easily customize the order, search URL, engine title or short keyword (such as being able to type "g {query}" to view Google results). However, similar functionality can be achieved using bookmarks, where the query's URL, keyword and title are all customizable [18]. However, adding search engines in Opera is not as easy as in Firefox - Opera offers no interface for doing so. Users have to manually edit a text file or use third-party software [19]).
Firefox's Gecko rendering engine is also seen as inferior in some ways to Opera's Presto rendering engine, especially in the areas of navigating forward and back [20], smooth image resizing [21] and page zooming [22]. As reported on May 5, 2005, a heavy work is in progress for achieving "blazingly fast" forward/backward [23]. The switching of the graphics infrastructure in Gecko to Cairo will also bring improved 2D graphics capabilities to the browser. This change is expected to be rolled out in version 1.9, which will be used by the version of Firefox after 1.1.
Criticisms from Mozilla Suite users
Many advanced configuration options available in Mozilla suite are hidden in Firefox, and can only be accessed by hand-editing configuration files or through the about:config interface.
The usual shortcuts of Mozilla in forms don't work any more in Firefox, e.g. CTRL-A marks all instead moving to the beginning of the line or CTRL-K doesn't delete to the end of the line anymore, but moves to the web search field and CTRL-W closes the browser window unconditionally, even when located inside an editable field.
Criticisms from Safari and Camino users
Firefox also attracts criticisms from users of Safari, and to a lesser extent, Camino. A key criticism is that Firefox uses nonstandard user interface widgets, as it is done in Safari and Camino, although it makes an attempt to emulate them.
Among the criticisms of Firefox's user interface is the fact that Firefox tabs lack individual close buttons, a feature found in both Safari and Camino. There is one button at the far right of the tab bar that closes the active tab, directly opposite the tabs in the window, which are left justified. This placement is justified by the argument that users are less likely to close a tab accidentally when switching tabs, especially when there are many tabs. Also, tabs can be closed in Firefox using the context menu and by middle-clicking the tab (although many Mac OS users would not have a second or third mouse button on their mice to take advantage of this capability). However, critics of this arrangement claim that the arrangement is too Windows-like, and by its nature, breaks Mac OS user interface guidelines (where guidelines dictate that the close button should be positioned in the far left instead).
Firefox uses a non-native implementation of form controls. This means that Firefox does not offer Mac OS X features such as built-in "spell check as you type" and speech services.
Because of the fact that Camino is another Mac browser from the Mozilla Foundation, which uses standard Cocoa widgets instead of the cross-platform XUL widgets found in Firefox, fans of Camino think of Firefox derisively as "the best browser that just happens to run on a Mac" while claiming Camino as "the best Mac browser". However, Camino is not as extensible as Firefox, and suffers from a smaller group of developers, and thus updates to Camino tend to be rare.
Criticisms from Internet suite users
Internet suites like Mozilla and Opera offer the same features as Firefox in a unified package with less memory consumption. This performance/usability issue is expected to be resolved when the stand-alone applications move toward the direction of XULRunner, where multiple XUL-based applications share the same runtime environment.