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• Help for local Users
• Courses with online Content
• Degree Requirements (ALL)
• Mathletes
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Web Page Help 1.2

Local Users Web Page Help <a href="filename"> </a>

This is the tag in HTML that creates a hyperlink to another Web page.

There are four general types of links distinguished by the location of the file you are linking to:

1. Specifying a URL for a file in the same directory:
   <a href="filename.html">Text you want user to see</a>
   The previous code produces a link that appears as:    Text you want user to see
2. Specifying a URL for a file in a subdirectory:
   <a href="subdir/filename.html">Text you want user to see</a>
3. Specifying a URL elsewhere on the same server: (Note beginning slash)
   <a href="/people/activities/index.php">Outdoor Activities</a>
   The previous code produces a link that appears as:    Outdoor Activities
4. Specifying a URL for a file on another web server:
   <a href="http://www.theregister.co.uk/2002/05/19/ms_in_peruvian_opensource_nightmare/"> M$ in Peruvian open-source nightmare</a>
   The previous code produces a link that appears as:    M$ in Peruvian open-source nightmare from The Register.

Other uses of the <a>...</a> tag

1. Creation of an email link:
   Please <a href="mailto:jarek@math.montana.edu_NOSPAM">email me</a> with your math questions.
2. 
   The previous code produces a link that appears as:    Please email me with your math questions.
3. The a href tag is also used to link to postscript and pdf files:
   PDF version of <a href="/~griff/courses/m240/Review/laplace.pdf">Laplace Transforms</a>
   The previous code produces a link that appears as:   PDF version of Laplace Transforms
4. The NAME attribute is used to specify links within a page.
   The links look like: <a href="#bottom">Bottom of the page</a>
   The previous code produces a link that appears as:    Bottom of the page
   You must specify where you want the browser to land with either an id attribute/value pair ( id="bottom") or a NAME anchor ( <a name="bottom"> ).
   OR another use: <a href="web_2.php#top">Return to Top of the page</a>
   The previous code produces a link that appears as:    Return to Top of the page
   Note, unlike other attributes, NAME is case-sensitive.
5. The Target attribute is mostly annoying. but occasionally there is a use like:
   <a href="/local/help/images/isaac.jpg" TARGET="NewWindow">Isaac</a> at a recent conference
   The previous code produces a link that appears as:    Isaac at a recent conference

Server Side Includes (SSI) provide a simple way to embed dynamic content into a web page. The main advantage of SSI over other embedding techniques is the simplicity of learning and using SSI.

A partial list of what is possible using SSI:

• Display information, such as filename, file modification time, etc.
• Include the contents of files.
• Utilize and display variables.
• Use simple conditional statements.
• Execute programs or commands.

SSI provide a simple means for simple tasks, and is not intended for complicated programming tasks. Once the directive is processed (and no errors occur) the appropriate text is added to the web page and NO trace of the SSI code remains.

Requirements

1. SSI must be 'allowed' in the directory. This is setup in the apache configuration file.
2. You must tell the server to parse the document for SSI. Also, setup in the apache configuration file.
   This is most easily done by using the extension .shtml.
   Our server has the XBitHack turned off.
3. Exact syntax followed - see below

SSI Tutorial

HTML uses the names <tag attribute="argument"> whereas
SSI uses <!--#directive argument="value"--> .

No spaces are allowed between the opening delimiter <!-- and the start of the command. Similarly, between the end of the command and -->, no spaces are allowed. And yes, this should look a lot like an HTML comment.
The result should look like this:
<!--#configfile="filename.html"-->. Failure to follow this simple rule will result in the server seeing a <!-- comment --> instead of what you intended.

Example:
We wish to include time of last modified information, first we configure the output as:
<!--#config timefmt="%D" -->
This is the time & date command: <!--#echo var="DATE_LOCAL"-->
Today is:
or using: <!--#config timefmt="%d %b %y"--> on <!--#echo var="LAST_MODIFIED"--> :
Last Modified:

• include -- this directive allows you to include the contents of one file into the current document.
  • Same Directory syntax:
    <!--#include file="schedule.inc.html"-->
  • Different Directory syntax:
    <!--#include virtual="/some/other/directory/schedule.inc.html"-->
• config -- changes some server default responses, also sets date formats.
  The function of the config directive is to "adjust" the server's responses to other directives. It takes two parts, the config directive followed by an instance of the directive. Both must reside inside the same HTML page.
• echo -- The echo directive works only with one argument, var="variable". However, the variable takes a wide variety of values.
  Examples: using: <!--#config timefmt="%c" -->
• • <!--#echo var="LAST_MODIFIED"--> Returns:
  • <!--#echo var="DATE_LOCAL"--> Returns:
  • <!--#echo var="DATE_GMT"--> Returns:
  • <!--#echo var="DOCUMENT_NAME"-->Returns:
  • <!--#echo var="DOCUMENT_URI"-->Returns:
  • <!--#echo var="SERVER_NAME"--> Returns:
  • <!--#echo var="SERVER_SOFTWARE"-->Returns:
  • <!--#echo var="HTTP_USER_AGENT"-->Returns:
  • <!--#echo var="GATEWAY_INTERFACE"-->Returns:
  • <!--#echo var="REMOTE_ADDR"--> Returns:
  • <!--#echo var="REMOTE_HOST"--> Returns:
  • <!--#echo var="REMOTE_USER"--> Returns:
• fsize -- returns the size of the stipulated file. Note, the output can be modified by the config directive.
• Same Directory syntax:
  <!--#fsize file="web_2.php"-->
  Returns:
  Different Directory syntax:
  <!--#fsize virtual="/people/faculty/images/rgriffiths.jpg"-->
  Returns:
• flastmod -- returns the last modified date and time of the stipulated file -- also modified by the config directive. (This directive does the same job as the echo directive's var="LAST_MODIFIED" argument and value.
  Same Directory syntax:
  <!--#flastmod file="web_2.php"-->
  Returns:
  Different Directory syntax:
  <!--#flastmod virtual="/people/faculty/images/rgriffiths.jpg"-->
  Returns:
• set directive allows for the creation of variables.
  syntax: <!--#set var="variable_name" value="variable_value"-->
  An example; on some document, say: page_1.shtml:

  <!--#set var="local_css" value="/~griff/include/really_silly.css"-->
  <!--#include virtual="/~griff/include/header.inc.shtml"-->
  

  Then in the file header.inc.shtml we have:

  <!--#if expr="$local_css"-->    
     <link rel="stylesheet" href="<!--#echo var='page_css'-->" type="text/css" /> 
  <!--#endif -->
  

• if Simple conditional tests using if/elsif/else/endif.
  syntax:

      <!--#if expr="test_condition_1"-->
             text rendered if test_condition_1 is true
      <!--#elif expr="test_condition_2"-->
             text rendered if test_condition_2 is true
      <!--#else-->
             text rendered if test_condition_1 AND test_condition_2 is False
      <!--#endif-->
  

  Examples:

      <!--#if expr="$DOCUMENT_NAME = /^HW/"-->    
          <link rel="stylesheet" href="/~griff/courses/include/style_assignment.css" 
               type="text/css" />
      <!--#else-->      
          <link rel="stylesheet" href="/~griff/courses/include/lec_mis.css" 
              type="text/css" />
      <!--#endif-->
  

       <!--#if expr="$REMOTE_ADDR = /^10.20.30./ || $REMOTE_ADDR = /^10.5./"-->
  	<li><a href="/local/help/">Local Users Help Page</a></li>
       <!--#endif -->
  

  If you see a link on the next line, the 'if' returned true
• Local Users Help Page
• exec inserts the execution of a command or CGI script. syntax:
  <!--#exec cmd="/bin/df -h /home"-->
  I have this feature turned off - everywhere (in the apache configuration).

A Final comment: When the page loads, the directives are executed, and assuming no errors are encountered, what appears when you view the source is the execution of the SSI not the actual directive.

Some References

• Apache Tutorial: Introduction to Server Side Includes
• Apache's eXtended Server Side Includes From O'Reilly's ONLamp.

CONFIG TIMEFMT

This table shows all the options which can be used with the config timefmt directive

option	description	e.g. (hard-coded)	e.g. (using DATE_LOCAL)
DAY
%a	abbreviated weekday	Tue	Sun
%A	weekday	Tuesday	Sunday
%d	day of month (01-31)	04	04
%e	day of month (1-31)	4	4
%w	day of week (0-6, Sunday=0)	2	0
%j	day of year (001 to 366)	186	247
WEEK (week 1 starts on first Sunday of year)
%U or %W	week number (00 to 53)	27	36
MONTH
%b	abbreviated month	Jul	Sep
%B	full month	July	September
%m	month (01 to 12)	07	09
YEAR
%y	two-digit year	00	05
%Y	year	2000	2005
DATE
%c	standard date and time	07/04/00 12:03:21	Sun Sep 4 17:08:23 2005
%x	standard date	07/04/00	09/04/05
%D	MM/DD/YY date	07/04/00	09/04/05
TIME
%X	standard time	12:03:21	17:08:23
%r	standard time in local notation	12:03:21 PM	05:08:23 PM
%T	standard time (24 hr clock)	12:03:21	17:08:23
%H	hour (00 to 23)	12	17
%I	hour (01 to 12)	12	05
%M	minute (00 to 59)	03	08
%S	seconds (00 to 59)	21	23
%p	AM or PM	PM	PM
%Z or %z	time zone	GMT Daylight Time	BST
LAYOUT
%n	new line

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