This is Info file w3.info, produced by Makeinfo version 1.68 from the input file w3.txi. INFO-DIR-SECTION World Wide Web INFO-DIR-SECTION GNU Emacs Lisp START-INFO-DIR-ENTRY * Emacs/W3: (w3). Emacs/W3 World Wide Web browser. END-INFO-DIR-ENTRY This file documents the Emacs/W3 World Wide Web browser. Copyright (C) 1993, 1994, 1995, 1996 William M. Perry Copyright (C) 1996, 1997 Free Software Foundation Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.  File: w3.info, Node: Other Variables, Prev: Hooks, Up: Advanced Features Miscellaneous variables ======================= There are lots of variables that control the real nitty-gritty of Emacs/W3 that the beginning user probably shouldn't mess with. Here they are. `url-bad-port-list' List of ports to warn the user about connecting to. Defaults to just the mail, NNTP and chargen ports so a malicious HTML author cannot spoof mail or news to other people. `url-confirmation-func' What function to use for asking yes or no functions. Possible values are `'yes-or-no-p' or `'y-or-n-p', or any function that takes a single argument (the prompt), and returns `t' only if a positive answer is gotten. Defaults to `'yes-or-no-p'. `url-passwd-entry-func' This is a symbol indicating which function to call to read in a password. If this variable is `nil' at startup, it is initialized depending on whether "EFS" or "ange-ftp" is being used. This function should accept the prompt string as its first argument, and the default value as its second argument. `url-max-password-attempts' When a protected document is requested, Emacs/W3 will prompt for a password. `url-max-password-attempts' controls how many attempts should be allowed, it is 5 by default. `w3-reuse-buffers' Determines what happens when `w3-fetch' is called on a document that has already been loaded into another buffer. Possible values are: `nil', `yes', and `no'. `nil' will ask the user if Emacs/W3 should reuse the buffer (this is the default value). A value of `yes' means assume the user wants to always reuse the buffer. A value of `no' means assume the user always wants to re-fetch the document. `url-show-status' Whether to show progress messages in the minibuffer. `url-show-status' controls if a running total of the number of bytes transferred is displayed. This Can cause a large performance hit if using a remote X display over a slow link, or a terminal with a slow modem. `mm-content-transfer-encodings' An assoc list of CONTENT-TRANSFER-ENCODINGS or CONTENT-ENCODINGS and the appropriate decoding algorithms for each. If the `cdr' of a node is a list, then this specifies the decoder is an external program, with the program as the first item in the list, and the rest of the list specifying arguments to be passed on the command line. If using an external decoder, it must accept its input from `stdin' and send its output to `stdout'. If the `cdr' of a node is a symbol whose function definition is non-`nil', then that encoding can be handled internally. The function is called with 2 arguments, buffer positions bounding the region to be decoded. The function should completely replace that region with the unencoded information. Currently supported transfer encodings are: base64, x-gzip, 7bit, 8bit, binary, x-compress, x-hqx, and quoted-printable. `url-uncompressor-alist' An assoc list of file extensions and the appropriate uncompression programs for each. This is used to build the Accept-encoding header for HTTP/1.0 requests. `w3-do-scripting' If this is non-`nil' then Emacs/W3 will do clien-side scripting. This is `nil' by default. `url-external-retrieval-program, url-external-retrieval-args' `url-external-retrieval-program' names the external program that is run to retrieve URLs. It is `www' by default. `url-external-retrieval-args' specifies the arguments that will be passed to it, `("-source")' by default. `w3-netscape-compatible-comments' Not everyone uses proper HTML comments. To allow for the presence of lesser browsers, Emacs/W3 will honour the incorrect netscape-style comments (`') if `w3-netscape-compatible-comments' is non-`nil'. This is `t' by default, but it shouldn't need to be. `font-blink-interval' This controls how often blinks occur for text inside `' tags. It is 0.5 seconds by default. `url-inhibit-mime-parsing' This controls whether to parse MIME headers in a message. If it is `nil' then the headers are parsed and deleted. `url-mime-language-string' This is used to set the contents of the `Accept-language:' field in HTTP/1.0 requests. If it is `nil' then the field isn't added and the server's default language version is retrieved, if it is `*' then the first available langauge version is retrieved. If it is a string, then it should be the desired language. `url-multiple-p' If this is non-`nil' then multiple queries are possible through ` *URL-*' buffers. `url-personal-mail-address' `url-personal-mail-address' contains your full email address. This is sent in the FROM field in an HTTP/1.0 request, but *Note Security:: for how to prevent this. If `nil' (the default), then it will be set to `user-mail-address' if non-`nil', else it will be `(user-real-login-name)' at `(system-name)'. `url-temporary-directory, w3-temporary-directory' `url-temporary-directory' and `w3-temporary-directory' control where temporary files are placed. If `TMPDIR' is set then they default to that, otherwise `/tmp'. `w3-documentation-root' This specifies the location of the Emacs/W3 documentation, it is `http://www.cs.indiana.edu/elisp/w3/' by default and *must* end in a slash. `w3-popup-menu-on-mouse-3' If you like context-sensitive menus then you're bound to like `w3-popup-menu-on-mouse-3'. If non-`nil' (the default) then Emacs/W3 will bind mouse-3 to provide context-sensitive menus. This might not work at the moment. If `w3-popup-menu-on-mouse-3' is `nil', then Emacs/W3 will not change the binding of mouse-3. `w3-track-mouse' If `w3-track-mouse' is non-`nil' (the default) then Emacs/W3 will display the URL under the mouse in the echo-area. `w3-use-menus' If `w3-use-menus' is `nil' then Emacs/W3 will not provide a menu interface. If it is `1', then Emacs/W3 will add a `W3' item to the Emacs menubar. If it is a list then Emacs/W3 will add its own menubar. The following symbols may appear in the list to control what Emacs/W3 puts in its menubar. `file' A list of file related commands `edit' Various standard editing commands (copy/paste) `view' Controlling various things about the document view `go' Navigation control `bookmark' Bookmark / hotlist control `options' Various options `buffers' The standard buffers menu `emacs' A toggle button to switch back to normal emacs menus `style' Control style information and who gets to set what `search' Various search engines `help' The help menu `nil' This may appear once in the list. All menus after this will be displayed flush right.  File: w3.info, Node: More Help, Next: Future Directions, Prev: Advanced Features, Up: Top More Help ********* For more help on Emacs/W3, please send me mail (wmperry+w3@cs.indiana.edu). Several discussion lists have also been created for Emacs/W3. To subscribe, send mail to majordomo@indiana.edu, with the body of the message 'subscribe LISTNAME '. All other mail should go to @indiana.edu. * w3-announce - this list is for anyone interested in Emacs/W3, and should in general only be used by me. The gnu.emacs.sources newsgroup and a few other mailing lists are included on this. Please only use this list for major package releases related to Emacs/W3. (www-announce@w3.org is included on this list). * w3-beta - this list is for beta testers of Emacs/W3. These brave souls test out not-quite stable code. * w3-dev - a list consisting of myself and a few other people who are interested in the internals of Emacs/W3, and doing active development work. Pretty dead right now, but I hope it will grow. For more help on the World Wide Web in general, please refer to the comp.infosystems.www.* newsgroups. There are also several discussion lists concerning the Web. Send mail to -request@w3.org with a subject line of 'subscribe '. All mail should go to @w3.org. Administrative mail should go to www-admin@w3.org. The lists are: * www-talk - for general discussion of the World Wide Web, where its going, new features, etc. All the major developers are subscribed to this list. * www-announce - for announcements concerning the World Wide Web. Server changes, new servers, new software, etc. As a last resort, mail me. I'll try to answer as quickly as I can.  File: w3.info, Node: Future Directions, Next: Reporting Bugs, Prev: More Help, Up: Top Future Directions ***************** Changes are constantly being made to the Emacs browser (hopefully all for the better). This is a list of the things that are being worked on right now. BUGS (4.0): - need to support HTTP/0.9 (http://c2.com:8080) responses - /etc/mailcap cannot overide builtin mm-mime-data stuff? - try to protect people from using '~' in file URLs - keystrokes entered while in w3-pause self-insert under XEmacs -- the loop around dispatch-event needs to be smarter about what it swallows. - border-color can have multiple color specifications, but we currently choke with 'args out of range' when we see this. - widget appears to be stealing button3 to mean 'activate' -- this is bogus! We lose all context-sensitive menus because of this. - We still seem to be growing the line size under Emacs 19.x/20.x - It would be really nice if w3 buffers were put into w3-mode as soon as they were created. Then if the rendering craps out somehow then the buffer could be browsed such as it was. Ideally, links and widgets would be functional. - document how to translate Netscape foo.pac files to emacs lisp - Should we stop using reporter.el? BUGS (4.1): - background colors are not heeded on table rows (). Same properties on individual cells or the table as a whole work fine. -
in
hosed -- margins in general tend to be too big sometimes. - client side imagemaps have to be in the same buffer (actually in the smae buffer, _BEFORE_ the usemap directive on an image) -- fix to be able to use imagemaps in different files, any position, etc, etc. FEATURES (4.1) - cache a formatted version of documents, with enough info to recreate the widgets in them. - w3-preview-region command - LDAP support (XEmacs) - New proxy type for sending requests via mail to a mail->web->mail gateway. - Emacspeak Interaction * some way of specifying in a stylesheet whether certain text is inaudible. use the 'inaudible text property for this. * Full Aural-CSS support - more sophisticated filling algorithm. I'm not sure exactly what would be sufficient but breaking lines after punctuation seems like it would solve most of the problem. - When fetching images for viewing (not inlining), W3 should at least have an option of displaying it inline, ala Netscape. - Widget library merging * Write a font selection widget * Write a voice selection widget * Write a mailcap entry widget - Custom library merging *Add custom support for MM - Hotlist handling * Abstract out current support * Do something similar to GNUS 'backends' to provide easy way to add new bookmark formats, etc. - Write a new major mode for handling CSS style sheets FEATURES (5.0) - Emacspeak Integration * Need option to turn off table rendering and print it out as a table that is viewable with emacspeak-table-ui.el - Write a text/xml parser - Completely rewrite display code again * Abstract everything out to follow parse->flow objects->render model * Base all stylesheet stuff off of DSSSL * CSS2 * New rendering backends - Native postscript output - LaTeX upgrade - TeXinfo - Display code * implement from netscape 3.0b5 * reimplement w3-show-headers * Handle math environment using the calc library * Better integration with the parser  File: w3.info, Node: Reporting Bugs, Next: Dealing with Firewalls, Prev: Future Directions, Up: Top Reporting Bugs ************** If any bugs are discovered in Emacs/W3, please report them to the mailing list w3-beta@indiana.edu -- this is where the brave souls who beta test the latest versions of Emacs/W3 reside, and are generally very responsive to bug reports. Please make sure to use the bug submission feature of Emacs/W3, so that all relevant information will be sent along with your bug report. By default this is bound to the `' key when in an Emacs/W3 buffer, or you can use from anywhere within Emacs. For problems that are causing emacs to signal and error, please send a backtrace. You can get a backtrace by `M-x setvariable RET debug-on-error RET t RET', and then reproduce the error. If the problem is visual, please capture a copy of the output and mail it along with the bug report (preferably as a MIME attachment, but anything will do). You can use the `xwd' program under X-windows for this, or under Windows 95/NT. Sorry, but I don't remember what the magic incarnation is for doing a screen dump under NeXTstep or OS/2. If the problem is actually causing Emacs to crash, then you will need to also mail the maintainers of the various Emacs distributions with the bug. Please use the gnu.emacs.bug newgroup for reporting bugs with GNU Emacs 19, and comp.emacs.xemacs for reporting bugs with XEmacs 19 or XEmacs 20. I am actively involved with the beta testing of the latest versions of both branches of Emacs, and if I can reproduce the problem, I will do my best to see it gets fixed in the next release. It is also important to always maintain as much context as possible in your responses. I get so much email from my various Emacs-activities and work, that I cannot remember everything. If you send a bug report, and I send you a reply, and you reply with 'no that didn't work', then odds are I will have no clue what didn't work, much less what that was trying to fix in the first place. It will be much quicker and less painful if I don't have to waste a round-trip email exchange saying 'what are you talking about'.  File: w3.info, Node: Dealing with Firewalls, Next: Proxy Gateways, Prev: Reporting Bugs, Up: Top Dealing with Firewalls ********************** By default, Emacs can support standard TCP/IP network connections on almost all the platforms it runs on (Unix, VMS, Windows, etc). However, there are several situations where it is not sufficient. Firewalls It is becoming more and more common to be behind a firewall or some other system that restricts your outbound network activity, especially if you are like me and away from the wonderful world of academia. Emacs/W3 has several different methods to get around firewalls (not to worry though -- none of them should get you in trouble with the local MIS department.) Emacs cannot resolve hostnames. This happens quite often on SunOS workstations and some ULTRIX machines. Some C libraries do not include the hostname resolver routines in their static libraries. If Emacs was linked statically, and was not linked with the resolver libraries, it wil not be able to get to any machines off the local network. This is characterized by being able to reach someplace with a raw ip number, but not its hostname (`http://129.79.254.191/' works, but `http://www.cs.indiana.edu/' doesn't). The best solution for this problem is to recompile Emacs, making sure to either link dynamically (if available on your operating system), or include the `-lresolv'. If you do not have the disk space or the appropriate permissions to recompile Emacs, another alternative is using the `nslookup' program to do hostname resolution. To turn this on, set the variable `url-gateway-broken-resolution' in your `~/.emacs' file. This runs the program specified by `url-gateway-nslookup-program' (by default "`nslookup'" to do hostname resolution. This program should expect a single argument on the command line -- the hostname to resolve, and should produce output similar to the standard Unix `nslookup' program: Name: www.cs.indiana.ed Address: 129.79.254.191 Using TERM (or TERM-like) Networking Software TERM (1) for slip-like access to the internet. NOTE: XEmacs and Emacs 19.22 or later have patches to enable native TERM networking. To enable it, `#define TERM' in the appropriate s/*.h file for the operating system, then change the `SYSTEM_LIBS' definition to include the `termnet' library that comes with the latest versions of TERM. If you run into any problems with the native TERM networking support in Emacs or XEmacs, please let wmperry+w3@cs.indiana.edu know, as he is responsible for the original support. Emacs/W3 has support for using the gateway mechanism for certain domains, and directly connecting to others. The variable `url-gateway-local-host-regexp' controls this behaviour. This is a regular expression (2) that matches local hosts that do not require the use of a gateway. If `nil', then all connections are made through the gateway. Emacs/W3 supports several methods of getting around gateways. The variable `url-gateway-method' controls which of these methods is used. This variable can have several values (use these as symbol names, not strings), ie: `(setq url-gateway-method 'telnet)'. Possible values are: "telnet" Use this method if you must first telnet and log into a gateway host, and then run telnet from that host to connect to outside machines. `url-gateway-telnet-host' The gateway host to telnet to. Once logged in there, you then telnet out to the hosts you want to connect to. `url-gateway-telnet-parameters' This should be a list of parameters to pass to the `telnet' program. `url-gateway-telnet-password-prompt' This is a regular expression that matches the password prompt when logging in. `url-gateway-telnet-login-prompt' This is a regular expression that matches the username prompt when logging in. `url-gateway-telnet-user-name' The username to log in with. `url-gateway-telnet-password' This is the password to send when logging in. `url-gateway-prompt-pattern' This is a regular expression that matches the shell prompt. "rlogin" This method is identical to the `telnet' method, but uses `rlogin' to log into the remote machine without having to send the username and password over the wire every time. `url-gateway-rlogin-host' Host to `rlogin' to before telnetting out. `url-gateway-rlogin-parameters' Parametres to pass to `rsh'. `url-gateway-rlogin-user-name' User name to use when logging in to the gateway. `url-gateway-prompt-pattern' This is a regular expression that matches the shell prompt. "tcp" Masanobu UMEDA (umerin@mse.kyutech.ac.jp) has written a very small application that you can run in a subprocess to do the network connections. "SOCKS" Use if the firewall has a SOCKS gateway running on it. SOCKS v5 protocol is defined in RFC1928. `socks-password' If this is `nil' then you will be asked for the passward, otherwise it will be used as the password for authenticating you to the SOCKS server. `socks-username' This is the username to use when authenticating yourself to the SOCKS server. By default this is your login name `socks-timeout' This controls how long, in seconds, Emacs/W3 will wait for responses from the SOCKS server; it is 5 by default. `socks-server' Thiss the default server, it take the form (`"Default server"' SERVER PORT VERSION) where VERSION can be either 4 or 5. `socks-server-aliases' This a list of server aliases. It is a list of aliases of the form (ALIAS HOSTNAME PORT VERSION). `socks-network-aliases' This a list of network aliases. Each entry in the list takes the form (ALIAS (NETWORK)) where ALIAS is a string that names the NETWORK. The networks can contain a pair (not a dotted pair) of IP addresses which specify a range of IP addresses, an IP address and a netmask, a domain name or a unique hostname or IP address. `socks-redirection-rules' This a list of redirection rules. Each rule take the form (DESTINATION NETWORK CONNECTION TYPE) where DESTINATION NETWORK is a network alias from `socks-network-aliases' and CONNECTION TYPE can be `nil' in which case a direct connection is used, or it can be an alias from `socks-server-aliases' in which case that server is used as a proxy. `socks-nslookup-program' This the `nslookup' program. It is `nslookup' by default. "native" This means that Emacs/W3 should use the builtin networking code of Emacs. This should be used only if there is no firewall, or the Emacs source has already been hacked to get around the firewall. Emacs/W3 should now be able to get outside the local network. If none of this makes sense, its probably my fault. Please check with the network administrators to see if they have a program that does most of this already, since somebody somewhere at the company has probably been through something similar to this before, and would be much more helpful/knowledgeable about the local setup than I would be. But feel free to mail me as a last resort. ---------- Footnotes ---------- (1) TERM is a user-level protocol for emulating IP over a serial line. More information is available at `ftp://sunsite.unc.edu/pub/Linux/apps/comm/term' (2) Please see the full Emacs distribution for a description of regular expressions  File: w3.info, Node: Proxy Gateways, Next: Installing SSL, Prev: Dealing with Firewalls, Up: Top Proxy Gateways ************** In late January 1993, Kevin Altis and Lou Montulli proposed and implemented a new proxy service. This service requires the use of environment variables to specify a gateway server/port # to send protocol requests to. Each protocol (HTTP, WAIS, gopher, FTP, etc.) can have a different gateway server. The environment variables are `PROTOCOL'_proxy, where `PROTOCOL' is one of the supported network protocols (gopher, file, HTTP, FTP, etc.) For companies with internal intranets, it will usually be helpful to define a list of hosts that should be contacted directly, not sent through the proxy. The `NO_PROXY' environment variable controls what hosts are able to be contacted directly. This should be a comma separated list of hostnames, domain names, or a mixture of both. Asterisks can be used as a wildcard. For example: NO_PROXY=*.aventail.com,home.com,*.seanet.com tells Emacs/W3 to contact all machines in the aventail.com and seanet.com domains directly, as well as the machine named home.com. For those adventurous souls who enjoy writing regular expressions, all the proxy settings can be manipulated from Emacs-Lisp. The variable `url-proxy-services' controls this. This is an assoc list, keyed on the protocol type (HTTP, gopher, etc) in all lowercase. The `cdr' of each entry should be the ADDRESS of the proxy server to contact, followed by ":" and the port number to use. In the case of the special "no_proxy" entry, it should be a regular expression that matches any hostnames that should be contacted directly. (setq url-proxy-services '(("http" . "proxy.aventail.com:80") ("no_proxy" . "^.*\\(aventail\\|seanet\\)\.com")))  File: w3.info, Node: Installing SSL, Next: Mailcap Files, Prev: Proxy Gateways, Up: Top Installing SSL ************** In order to use SSL in Emacs/W3, an implementation of SSL is necessary. Emacs/W3 is configued to work out of the box with SSLeay 0.6.6 or later. For best results, you should apply a patch that makes the SSLeay client much quieter about what it reports. You can download SSLeay from `ftp://ftp.psy.uq.oz.au/pub/Crypto/SSL/' The following variables control how the external program is invoked. `ssl-program-name' The name of the program to run, as a string. (setq ssl-program-name "s_client") `ssl-program-arguments' This should be used if your SSL program needs command line switches to specify any behaviour (certificate file locations, etc). This is a list of strings and symbols. The special symbols 'host and 'port may be used in the list of arguments and will be replaced with the hostname and service/port that will be connected to. (setq ssl-program-arguments '("-host" host "-port" service "-verify" "4" "-CApath /usr/local/ssl/certs")) The default is ("-host" host "-port" service "-verify" SSL-CERTIFICATE-VERIFICATION-POLICY -CApath SSL-CERTIFICATE-DIRECTORY). `ssl-certificate-directory' is the directory in which CA certificates are stored. It is `W3-CONFIGURATION-DIRECTORY/cert' by default. `ssl-rehash-program-name' is the program that is run after adding a certificate to the `ssl-certificate-directory' directory. It is run with the directory name as an argument and defaults to `c_rehash'. `ssl-view-certificate-program-name' names the program that can produce a human-readable view of a certificate. It is `x509' by default and is called with the arguments listed in `ssl-view-certificate-program-arguments' which is `("text" "-inform" "DER")' by default. `ssl-certificate-directory-style' specifies the type of certificate database to use. It's default (and at the moment, only possible value) is `ssleay' which specifies a directory or pem encoded certificates with hash symlinks. You can decide how high up the chain of certificates should be verified by setting `ssl-certificate-verification-policy'. Possible values are 0 No verification 1 Verification required 3 Reject connection if verification fails 5 SSL_VERIFY_CLIENT_ONCE The default is 0  File: w3.info, Node: Mailcap Files, Next: Down with DoubleClick, Prev: Installing SSL, Up: Top Mailcap Files ************* NCSA Mosaic and almost all other WWW browsers rely on a separate file for mapping MIME types to external viewing programs. This takes some of the burden off of browser developers, so each browser does not have to support all image formats, or postscript, etc. Instead of having the users of Emacs/W3 duplicate this in lisp, this file can be parsed using the `mm-parse-mailcaps' function. This function is called each time Emacs/W3 is loaded. It tries to locate mimetype files in several places. If the environment variable `MAILCAPS' is nonempty, then this is assumed to specify a UNIX-like path of mimetype files (this is a colon separated string of pathnames). If the `MAILCAPS' environment variable is empty, then Emacs/W3 looks for these files: 1. `~/.mailcap' 2. `/etc/mailcap' 3. `/usr/etc/mailcap' 4. `/usr/local/etc/mailcap' This format of this file is specified in RFC 1343, but a brief synopsis follows (this is taken verbatim from sections of RFC 1343). Each mailcap file consists of a set of entries that describe the proper handling of one media type at the local site. For example, one line might tell how to display a message in Group III fax format. A mailcap file consists of a sequence of such individual entries, separated by newlines (according to the operating system's newline conventions). Blank lines and lines that start with the "#" character (ASCII 35) are considered comments, and are ignored. Long entries may be continued on multiple lines if each non-terminal line ends with a backslash character ('\', ASCII 92), in which case the multiple lines are to be treated as a single mailcap entry. Note that for such "continued" lines, the backslash must be the last character on the line to be continued. Each mailcap entry consists of a number of fields, separated by semi-colons. The first two fields are required, and must occur in the specified order. The remaining fields are optional, and may appear in any order. The first field is the content-type, which indicates the type of data this mailcap entry describes how to handle. It is to be matched against the type/subtype specification in the "Content-Type" header field of an Internet mail message. If the subtype is specified as "*", it is intended to match all subtypes of the named content-type. The second field, view-command, is a specification of how the message or body part can be viewed at the local site. Although the syntax of this field is fully specified, the semantics of program execution are necessarily somewhat operating system dependent. The optional fields, which may be given in any order, are as follows: * The "compose" field may be used to specify a program that can be used to compose a new body or body part in the given format. Its intended use is to support mail composing agents that support the composition of multiple types of mail using external composing agents. As with the view- command, the semantics of program execution are operating system dependent. The result of the composing program may be data that is not yet suitable for mail transport--that is, a Content-Transfer-Encoding may need to be applied to the data. * The "composetyped" field is similar to the "compose" field, but is to be used when the composing program needs to specify the Content-type header field to be applied to the composed data. The "compose" field is simpler, and is preferred for use with existing (non-mail-oriented) programs for composing data in a given format. The "composetyped" field is necessary when the Content-type information must include auxilliary parameters, and the composition program must then know enough about mail formats to produce output that includes the mail type information. * The "edit" field may be used to specify a program that can be used to edit a body or body part in the given format. In many cases, it may be identical in content to the "compose" field, and shares the operating-system dependent semantics for program execution. * The "print" field may be used to specify a program that can be used to print a message or body part in the given format. As with the view-command, the semantics of program execution are operating system dependent. * The "test" field may be used to test some external condition (e.g. the machine architecture, or the window system in use) to determine whether or not the mailcap line applies. It specifies a program to be run to test some condition. The semantics of execution and of the value returned by the test program are operating system dependent. If the test fails, a subsequent mailcap entry should be sought. Multiple test fields are not permitted--since a test can call a program, it can already be arbitrarily complex. * The "needsterminal" field indicates that the view-command must be run on an interactive terminal. This is needed to inform window-oriented user agents that an interactive terminal is needed. (The decision is not left exclusively to the view-command because in some circumstances it may not be possible for such programs to tell whether or not they are on interactive terminals.) The needsterminal command should be assumed to apply to the compose and edit commands, too, if they exist. Note that this is NOT a test--it is a requirement for the environment in which the program will be executed, and should typically cause the creation of a terminal window when not executed on either a real terminal or a terminal window. * The "copiousoutput" field indicates that the output from the view-command will be an extended stream of output, and is to be interpreted as advice to the UA (User Agent mail- reading program) that the output should be either paged or made scrollable. Note that it is probably a mistake if needsterminal and copiousoutput are both specified. * The "description" field simply provides a textual description, optionally quoted, that describes the type of data, to be used optionally by mail readers that wish to describe the data before offering to display it. * The "x11-bitmap" field names a file, in X11 bitmap (xbm) format, which points to an appropriate icon to be used to visually denote the presence of this kind of data. * Any other fields beginning with "x-" may be included for local or mailer-specific extensions of this format. Implementations should simply ignore all such unrecognized fields to permit such extensions, some of which might be standardized in a future version of this document.  File: w3.info, Node: Down with DoubleClick, Next: Temporary, Prev: Mailcap Files, Up: Top Down with DoubleClick ********************* :: WORK :: Document why doubleclick is evil :: WORK :: Document how you can never see another ad from them again  File: w3.info, Node: Temporary, Next: General Index, Prev: Down with DoubleClick, Up: Top