about: URL (Request method)

This is a special kind of URL that fetches content from a storage area inside the Netscape browser instead from using HTTP to get it from a web server.


JavaScript - 1.1
JScript - 3.0
Internet Explorer - 4.0
Netscape - 3.0

This is a special request method provided by the Netscape browser to gain access to local client-side resources. The resources are loaded from inside the application itself.

In the Macintosh version of Navigator, this means they are stored in the resource fork of the browser application. If you need to deploy a custom version of Navigator within an Intranet environment, with some care you can modify these resources with a resource-editing tool, such as ResEdit. Always work on a copy of the application and test the changes thoroughly.

On other platforms, the resources are likely to be stored in files located in folders adjacent to the application. You will need to study your own copy of Netscape to see what you can change.

These special URLs are mostly not present in early versions of MSIE, although there will be some internal resources which may provide customization opportunities. MSIE also supports an about:blank URL that provides a blank page. There may be others hidden away inside the application.

You may also be able to obtain administration tools from Netscape and Microsoft to carry out legitimate customizations on the browsers before deploying them throughout your organization.

The following special URLs seem to work when typed into the location box:

about:logoNetscape logo
about:mozillaA fire & brimstone quote from the book of Mozilla (Yes it's really there - at least on some versions)
about:authorsShows a cryptic message about the page having been removed, although the authors.html file is still present inside the application..
about:cacheDisplays a disk cache report
about:documentDisplays the document info console.
about:fontsDisplays the font info console.
about:globalA global history report
about:image-cacheA report on the internal image cache
about:licenseA hyperlink to the Netscape license document
about:mailintroDisplays the Netscape mail info page.
about:memory-cacheA report on the memory cache
about:picsGenerates a security exception
about:pluginsA page of information about the plugins
about:security?advisor=XXXBrings up a security console where XXX indicates the window to operate on.
about:security?banner-insecureServes an unlocked padlock image
about:security?banner-secureServes a locked padlock image
about:security?issuer-logo=XXXReturns a graphic where XXX identifies which one
about:security?subject-logo=XXXReturns a graphic where XXX identifies which one
about:coslogo2Cosmo logo
about:fclogoFull Circle software logo
about:hslogoBeatnik logo
about:hypeAn audio clip
about:insologoInso logo
about:javalogoJava compatible logo
about:litronicLitronic logo
about:mclogoMarimba Castanet logo
about:mmlogoMacromedia logo
about:ncclogoNetcast logo
about:odilogoObject Design logo
about:qtlogoApple QuickTime logo
about:rsalogoRSA secure logo
about:symlogoSymantec logo
about:tdlogoTrueDoc logo
about:visilogoVisiGenic logo
about:blankPresents a blank page on Netscape Navigator 3 and MSIE version 5. It is used to create a blank page when a new window is opened.

Some of these URLs can be used in frames, but others can't. A few can be used as HREF values. JavaScript complains that the about: request method is illegal. This means you cannot change the location.href within a page to any of the "about:" URLs. However, you might be able to write some innerHTML content into a <DIV> or <SPAN> to place a link to these assets.

Many of the built in assets are used as image sources in the about page. It's possible you might want to display the Netscape logo. If you are aware that you are using software provided by the other third parties, you might (if they give you permission) place their logo on the screen when you are using features of their software. You should ask first, although Netscape probably won't mind their logo being served like this.

The interesting thing about this is that you are effectively serving assets out of a static cache in the client file system.

The URL that points at the license document may be useful as it is possible you might want to display the Netscape license if you are redistributing the browser.

The about:plugins URL yields a page containing some useful JavaScript that displays the plugins page. You may find some useful techniques in here for managing plugin facilities although they may be Netscape compatible only.

Mostly, these special URLs will be useful for debugging. Getting details of the disk cache, for example, may be useful. Pulling up the JavaScript debugger page if you detect an error in your script might also be a cool trick.

The MSIE and Netscape browsers can both use the about:blank URL value as a default page when the browser is started up.


See also:javascript: URL, nethelp: URL, UniversalBrowserAccess, UniversalBrowserRead, URL