cgi.3

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

\&                             ]
\&                     );
.Ve
.PP
And here's how to create an HTTP-EQUIV <meta> tag:
.PP
.Vb 2
\&      print start_html(\-head=>meta({\-http_equiv => \*(AqContent\-Type\*(Aq,
\&                                    \-content    => \*(Aqtext/html\*(Aq}))
.Ve
.PP
\&\s-1JAVASCRIPTING:\s0 The \fB\-script\fR, \fB\-noScript\fR, \fB\-onLoad\fR,
\&\fB\-onMouseOver\fR, \fB\-onMouseOut\fR and \fB\-onUnload\fR parameters are used
to add Netscape JavaScript calls to your pages.  \fB\-script\fR should
point to a block of text containing JavaScript function definitions.
This block will be placed within a <script> block inside the \s-1HTML\s0 (not
\&\s-1HTTP\s0) header.  The block is placed in the header in order to give your
page a fighting chance of having all its JavaScript functions in place
even if the user presses the stop button before the page has loaded
completely.  \s-1CGI\s0.pm attempts to format the script in such a way that
JavaScript-naive browsers will not choke on the code: unfortunately
there are some browsers, such as Chimera for Unix, that get confused
by it nevertheless.
.PP
The \fB\-onLoad\fR and \fB\-onUnload\fR parameters point to fragments of JavaScript
code to execute when the page is respectively opened and closed by the
browser.  Usually these parameters are calls to functions defined in the
\&\fB\-script\fR field:
.PP
.Vb 10
\&      $query = new CGI;
\&      print header;
\&      $JSCRIPT=<<END;
\&      // Ask a silly question
\&      function riddle_me_this() {
\&         var r = prompt("What walks on four legs in the morning, " +
\&                       "two legs in the afternoon, " +
\&                       "and three legs in the evening?");
\&         response(r);
\&      }
\&      // Get a silly answer
\&      function response(answer) {
\&         if (answer == "man")
\&            alert("Right you are!");
\&         else
\&            alert("Wrong!  Guess again.");
\&      }
\&      END
\&      print start_html(\-title=>\*(AqThe Riddle of the Sphinx\*(Aq,
\&                               \-script=>$JSCRIPT);
.Ve
.PP
Use the \fB\-noScript\fR parameter to pass some \s-1HTML\s0 text that will be displayed on 
browsers that do not have JavaScript (or browsers where JavaScript is turned
off).
.PP
The <script> tag, has several attributes including \*(L"type\*(R" and src.
The latter is particularly interesting, as it allows you to keep the
JavaScript code in a file or \s-1CGI\s0 script rather than cluttering up each
page with the source.  To use these attributes pass a \s-1HASH\s0 reference
in the \fB\-script\fR parameter containing one or more of \-type, \-src, or
\&\-code:
.PP
.Vb 4
\&    print $q\->start_html(\-title=>\*(AqThe Riddle of the Sphinx\*(Aq,
\&                         \-script=>{\-type=>\*(AqJAVASCRIPT\*(Aq,
\&                                   \-src=>\*(Aq/javascript/sphinx.js\*(Aq}
\&                         );
\&
\&    print $q\->(\-title=>\*(AqThe Riddle of the Sphinx\*(Aq,
\&               \-script=>{\-type=>\*(AqPERLSCRIPT\*(Aq,
\&                         \-code=>\*(Aqprint "hello world!\en;"\*(Aq}
\&               );
.Ve
.PP
A final feature allows you to incorporate multiple <script> sections into the
header.  Just pass the list of script sections as an array reference.
this allows you to specify different source files for different dialects
of JavaScript.  Example:
.PP
.Vb 10
\&     print $q\->start_html(\-title=>\*(AqThe Riddle of the Sphinx\*(Aq,
\&                          \-script=>[
\&                                    { \-type => \*(Aqtext/javascript\*(Aq,
\&                                      \-src      => \*(Aq/javascript/utilities10.js\*(Aq
\&                                    },
\&                                    { \-type => \*(Aqtext/javascript\*(Aq,
\&                                      \-src      => \*(Aq/javascript/utilities11.js\*(Aq
\&                                    },
\&                                    { \-type => \*(Aqtext/jscript\*(Aq,
\&                                      \-src      => \*(Aq/javascript/utilities12.js\*(Aq
\&                                    },
\&                                    { \-type => \*(Aqtext/ecmascript\*(Aq,
\&                                      \-src      => \*(Aq/javascript/utilities219.js\*(Aq
\&                                    }
\&                                 ]
\&                             );
.Ve
.PP
The option \*(L"\-language\*(R" is a synonym for \-type, and is supported for
backwad compatibility.
.PP
The old-style positional parameters are as follows:
.IP "\fBParameters:\fR" 4
.IX Item "Parameters:"
.PD 0
.IP "1." 4
.IX Item "1."
.PD
The title
.IP "2." 4
.IX Item "2."
The author's e\-mail address (will create a <link rev=\*(L"\s-1MADE\s0\*(R"> tag if present
.IP "3." 4
.IX Item "3."
A 'true' flag if you want to include a <base> tag in the header.  This
helps resolve relative addresses to absolute ones when the document is moved, 
but makes the document hierarchy non-portable.  Use with care!
.IP "4, 5, 6..." 4
.IX Item "4, 5, 6..."
Any other parameters you want to include in the <body> tag.  This is a good
place to put Netscape extensions, such as colors and wallpaper patterns.
.Sh "\s-1ENDING\s0 \s-1THE\s0 \s-1HTML\s0 \s-1DOCUMENT:\s0"
.IX Subsection "ENDING THE HTML DOCUMENT:"
.Vb 1
\&        print end_html
.Ve
.PP
This ends an \s-1HTML\s0 document by printing the </body></html> tags.
.Sh "\s-1CREATING\s0 A SELF-REFERENCING \s-1URL\s0 \s-1THAT\s0 \s-1PRESERVES\s0 \s-1STATE\s0 \s-1INFORMATION:\s0"
.IX Subsection "CREATING A SELF-REFERENCING URL THAT PRESERVES STATE INFORMATION:"
.Vb 2
\&    $myself = self_url;
\&    print q(<a href="$myself">I\*(Aqm talking to myself.</a>);
.Ve
.PP
\&\fIself_url()\fR will return a \s-1URL\s0, that, when selected, will reinvoke
this script with all its state information intact.  This is most
useful when you want to jump around within the document using
internal anchors but you don't want to disrupt the current contents
of the form(s).  Something like this will do the trick.
.PP
.Vb 4
\&     $myself = self_url;
\&     print "<a href=\e"$myself#table1\e">See table 1</a>";
\&     print "<a href=\e"$myself#table2\e">See table 2</a>";
\&     print "<a href=\e"$myself#yourself\e">See for yourself</a>";
.Ve
.PP
If you want more control over what's returned, using the \fB\f(BIurl()\fB\fR
method instead.
.PP
You can also retrieve the unprocessed query string with \fIquery_string()\fR:
.PP
.Vb 1
\&    $the_string = query_string;
.Ve
.Sh "\s-1OBTAINING\s0 \s-1THE\s0 \s-1SCRIPT\s0'S \s-1URL\s0"
.IX Subsection "OBTAINING THE SCRIPT'S URL"
.Vb 7
\&    $full_url      = url();
\&    $full_url      = url(\-full=>1);  #alternative syntax
\&    $relative_url  = url(\-relative=>1);
\&    $absolute_url  = url(\-absolute=>1);
\&    $url_with_path = url(\-path_info=>1);
\&    $url_with_path_and_query = url(\-path_info=>1,\-query=>1);
\&    $netloc        = url(\-base => 1);
.Ve
.PP
\&\fB\f(BIurl()\fB\fR returns the script's \s-1URL\s0 in a variety of formats.  Called
without any arguments, it returns the full form of the \s-1URL\s0, including
host name and port number
.PP
.Vb 1
\&    http://your.host.com/path/to/script.cgi
.Ve
.PP
You can modify this format with the following named arguments:
.IP "\fB\-absolute\fR" 4
.IX Item "-absolute"
If true, produce an absolute \s-1URL\s0, e.g.
.Sp
.Vb 1
\&    /path/to/script.cgi
.Ve
.IP "\fB\-relative\fR" 4
.IX Item "-relative"
Produce a relative \s-1URL\s0.  This is useful if you want to reinvoke your
script with different parameters. For example:
.Sp
.Vb 1
\&    script.cgi
.Ve
.IP "\fB\-full\fR" 4
.IX Item "-full"
Produce the full \s-1URL\s0, exactly as if called without any arguments.
This overrides the \-relative and \-absolute arguments.
.IP "\fB\-path\fR (\fB\-path_info\fR)" 4
.IX Item "-path (-path_info)"
Append the additional path information to the \s-1URL\s0.  This can be
combined with \fB\-full\fR, \fB\-absolute\fR or \fB\-relative\fR.  \fB\-path_info\fR
is provided as a synonym.
.IP "\fB\-query\fR (\fB\-query_string\fR)" 4
.IX Item "-query (-query_string)"
Append the query string to the \s-1URL\s0.  This can be combined with
\&\fB\-full\fR, \fB\-absolute\fR or \fB\-relative\fR.  \fB\-query_string\fR is provided
as a synonym.
.IP "\fB\-base\fR" 4
.IX Item "-base"
Generate just the protocol and net location, as in http://www.foo.com:8000
.IP "\fB\-rewrite\fR" 4
.IX Item "-rewrite"
If Apache's mod_rewrite is turned on, then the script name and path
info probably won't match the request that the user sent. Set
\&\-rewrite=>1 (default) to return URLs that match what the user sent
(the original request \s-1URI\s0). Set \-rewrite\->0 to return URLs that match
the \s-1URL\s0 after mod_rewrite's rules have run. Because the additional
path information only makes sense in the context of the rewritten \s-1URL\s0,
\&\-rewrite is set to false when you request path info in the \s-1URL\s0.
.Sh "\s-1MIXING\s0 \s-1POST\s0 \s-1AND\s0 \s-1URL\s0 \s-1PARAMETERS\s0"
.IX Subsection "MIXING POST AND URL PARAMETERS"
.Vb 1
\&   $color = url_param(\*(Aqcolor\*(Aq);
.Ve
.PP
It is possible for a script to receive \s-1CGI\s0 parameters in the \s-1URL\s0 as
well as in the fill-out form by creating a form that POSTs to a \s-1URL\s0
containing a query string (a \*(L"?\*(R" mark followed by arguments).  The
\&\fB\f(BIparam()\fB\fR method will always return the contents of the POSTed
fill-out form, ignoring the \s-1URL\s0's query string.  To retrieve \s-1URL\s0
parameters, call the \fB\f(BIurl_param()\fB\fR method.  Use it in the same way as
\&\fB\f(BIparam()\fB\fR.  The main difference is that it allows you to read the
parameters, but not set them.
.PP
Under no circumstances will the contents of the \s-1URL\s0 query string
interfere with similarly-named \s-1CGI\s0 parameters in POSTed forms.  If you
try to mix a \s-1URL\s0 query string with a form submitted with the \s-1GET\s0
method, the results will not be what you expect.
.SH "CREATING STANDARD HTML ELEMENTS:"
.IX Header "CREATING STANDARD HTML ELEMENTS:"
\&\s-1CGI\s0.pm defines general \s-1HTML\s0 shortcut methods for most, if not all of
the \s-1HTML\s0 3 and \s-1HTML\s0 4 tags.  \s-1HTML\s0 shortcuts are named after a single
\&\s-1HTML\s0 element and return a fragment of \s-1HTML\s0 text that you can then
print or manipulate as you like.  Each shortcut returns a fragment of
\&\s-1HTML\s0 code that you can append to a string, save to a file, or, most
commonly, print out so that it displays in the browser window.
.PP
This example shows how to use the \s-1HTML\s0 methods:
.PP
.Vb 7
\&   print $q\->blockquote(
\&                     "Many years ago on the island of",
\&                     $q\->a({href=>"http://crete.org/"},"Crete"),
\&                     "there lived a Minotaur named",
\&                     $q\->strong("Fred."),
\&                    ),
\&       $q\->hr;
.Ve
.PP
This results in the following \s-1HTML\s0 code (extra newlines have been
added for readability):
.PP
.Vb 6
\&   <blockquote>
\&   Many years ago on the island of
\&   <a href="http://crete.org/">Crete</a> there lived
\&   a minotaur named <strong>Fred.</strong> 
\&   </blockquote>
\&   <hr>
.Ve
.PP
If you find the syntax for calling the \s-1HTML\s0 shortcuts awkward, you can
import them into your namespace and dispense with the object syntax
completely (see the next section for more details):
.PP
.Vb 8
\&   use CGI \*(Aq:standard\*(Aq;
\&   print blockquote(
\&      "Many years ago on the island of",
\&      a({href=>"http://crete.org/"},"Crete"),
\&      "there lived a minotaur named",
\&      strong("Fred."),
\&      ),
\&      hr;
.Ve
.Sh "\s-1PROVIDING\s0 \s-1ARGUMENTS\s0 \s-1TO\s0 \s-1HTML\s0 \s-1SHORTCUTS\s0"
.IX Subsection "PROVIDING ARGUMENTS TO HTML SHORTCUTS"
The \s-1HTML\s0 methods will accept zero, one or multiple arguments.  If you
provide no arguments, you get a single tag:
.PP
.Vb 1
\&   print hr;    #  <hr>
.Ve
.PP
If you provide one or more string arguments, they are concatenated
together with spaces and placed between opening and closing tags:
.PP
.Vb 1
\&   print h1("Chapter","1"); # <h1>Chapter 1</h1>"
.Ve
.PP
If the first argument is an associative array reference, then the keys
and values of the associative array become the \s-1HTML\s0 tag's attributes:
.PP
.Vb 2
\&   print a({\-href=>\*(Aqfred.html\*(Aq,\-target=>\*(Aq_new\*(Aq},
\&      "Open a new frame");
\&
\&            <a href="fred.html",target="_new">Open a new frame</a>
.Ve
.PP
You may dispense with the dashes in front of the attribute names if
you prefer:
.PP
.Vb 1
\&   print img {src=>\*(Aqfred.gif\*(Aq,align=>\*(AqLEFT\*(Aq};
\&
\&           <img align="LEFT" src="fred.gif">
.Ve
.PP
Sometimes an \s-1HTML\s0 tag attribute has no argument.  For example, ordered
lists can be m