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 ::   Intro to Perl/CGI and HTML Forms
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 ::   Intro to Perl 5
 ::   Intro to Perl
 ::   Intro to Perl Taint mode
 ::   Sherlock Holmes and the Case of the Broken CGI Script
 ::   Writing COM Components in Perl

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 ::   Cross Browser Java

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 ::   Intro to The Web Application Development Environment
 ::   Introduction to XML
 ::   Intro to Web Design
 ::   Intro to Web Security
 ::   Databases for Web Developers
 ::   UNIX for Web Developers
 ::   Intro to Adobe Photoshop
 ::   Web Programming 101
 ::   Introduction to Microsoft DNA

Misc non-technical tutorials
 ::   Misc Technopreneurship Docs
 ::   What is a Webmaster?
 ::   What is the open source business model?
 ::   Technical writing
 ::   Small and mid-sized businesses on the Web

Offsite tutorials
 ::   ISAPI Perl Primer
 ::   Serving up web server basics
 ::   Introduction to Java (Parts 1 and 2) in Slovak


introduction to web programming
Printing with Perl  
The most basic method for sending text to the Web browser is the "print" function in Perl. The print function uses the following syntax:

     print "[string to print]";

By default, the print function outputs data to standard output "<STDOUT>" which in the case of a CGI application, is the Web browser. Thus, whatever you tell Perl to print will be sent to the Web browser to be displayed.

For example, the following CGI script sends the phrase, "Hello Cyberspace" to the Web browser:

     print "Content-type: text/html\n\n";
     print "Hello Cyberspace";

However, print does have some limitations. For example, the print function is limited in its ability to handle Perl special characters within an output string. For example, suppose we want to print the HTML code:

     <A HREF =

You might extrapolate from the syntax above, that you would use the following Perl code to display the hyperlink:

print "Content-type: text/html\n\n";
print "<A HREF =

Unfortunately, this would yield a syntax error. Additionally, because this is a very common line of HTML, it is a common source of Perl CGI customization errors. The problem lies in the incorporation of the at sign (@) and double-quote (") characters within the code.

As it so happens, these characters are "special" Perl characters. In other words, they each have special meaning to Perl and, when displaying them, you must take precautions so that Perl understands what you are asking for.

For example, consider the double quote marks in the "mailto" hyperlink. How would Perl know that the double quote marks in the "mailto" hyperlink are supposed to be part of the string to be printed and not actually the end of the string to be printed? Recall that we use the double quote marks to delineate the beginning and the ending of a text string to be printed. Similarly, the at sign (@) is used by Perl to name list arrays.

Many other "special" characters exist and are discussed in other Perl references.

One solution to this problem is to escape the Perl special characters with a backslash (\). The backslash character tells Perl that whatever character follows should be considered a part of the string and not a special character. Thus, the correct syntax for the mailto hyperlink would be:

print "Content-type: text/html\n\n";
print "<A HREF =

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