Script Tags Scripting
Script is inserted using the <?php opening tag and ?> closing tag. A
closing tag at the end of a file is not required thus avoiding the insertion
of unnecessary trailing white space. The <php= opening shortcut can be used
with the following content assumed to be parameters to an ECHO statement.
With JANOS scripting the preference is to use the generic scripting tags <?
and ?>. The "php" characters are optional in the opening tags. So to add lines
of script you can just use <? or for the shorthand echo statement <?=.
The JANOS Web Server interprets PHP script in files with the .PHP extension.
The index.php file is a default home page which if it exists takes precedence
over and index.html file. The PHP file is assumed to contain HTML content
which would be served like any other page with the exception of any script
which is identified by the special tags. A .PHP file when served first
executes script (if any) generating a .HTML file which subsequently is
served to the client browser. Scripts then are designed to render HTML.
From the JANOS Command Line you can execute Batch Files which have the
.BAT extension. Script may be interposed in these files for pre-processing.
The syntax is identical to that used in the HTML implementation including
the <? and ?> tags. The script renders commands formatted as if entered
at the command line which are then executed. You can use script to
conditionally customize and/or generate the commands.
The scripting implementation is very powerful. While such scripting is usually
implemented by an interpreter, JANOS compiles these scripts prior to execution
and caches the compiled code for reuse. As a result scripts execute fast and
efficiently. This can be used to create utility and even application programs.
A Program File can be created with the default extension .PRG and executed
directly using the RUN command. These program files are logically created
just as PHP HTML pages or scripted batch files. One or more blocks of script
are interposed using the <? and ?> tags. In this case, text outside of
the script is merely echoed as program output.
Script may be entered at the command line. The line must begin with the
opening <? tag and be terminated with ?>. The script therein generates
the command that then is executed. This can be useful in testing fragments
Inline script entered in this fashion must also simulate an ENTER keystroke
by including a trailing newline character '\n'. Output without the newline
is simply displayed and execution is not attempted. The puts($string)
function echos the $string followed by the necessary carriage return and
linefeed for execution. For example:
bruce_dev /> <? puts("date");?>
Sun Jun 27 08:02:45 EDT 2021
bruce_dev /> <? echo "date\n";?>
Sun Jun 27 08:03:02 EDT 2021
bruce_dev /> <?="date\n";?>
Sun Jun 27 08:03:11 EDT 2021
bruce_dev /> <?="date";?>
Inline script can also simply generate output that would not be interpreted
as a command. a Line of script may be entered following an exclamation
point '!'. This syntax assumes the opening and closing tags. These should
not then be entered. For example:
bruce_dev /> ! puts("Hello World.");
Errors in scripts are reported in the php.log file. Inline script errors
are reported to the console.
bruce_dev /> <? echo "Hello World." ?>
Scripting error: /temp/tmp31076 (Line 1)
1: <? echo "Hello World." ?>
1: ^ expected semicolon
HELP Topics: VARIABLES