PHP was originally designed to be used in conjunction with a web server, and in the case of the LAMP
architecture, the Apache Web Server. PHP applications are designed embedding PHP scripts within a web
page along with its HTML. Unlike standard HTML pages which are sent directly from the web server to
the end user, PHP files are first interpreted by the PHP application which then converts the PHP script into
another form for display. This process eliminates the end user from being able to see the original PHP
script that was embedded in the HTML and provides true interaction in HTML files. This process is
similar to proprietary applications such as ASP and Coldfusion; however, PHP is Open Source and cross-
platform.
PHP Tags
PHP scripts are distinguished from the HTML scripts by using delimiting characters that tell the server to
execute the PHP application to interpret that which is contained in the code. There are four ways to
accomplish this; however, the first two listed below are the safest for portability and conflict prevention:
• Default Syntax - The default syntax is starting the PHP script with <?php and closing out the script
with ?>. The following example demonstrates how this would look within HTML code:
<html><head><title>PHP Default Syntax</title></head>
<body>
<h3>PHP Default Syntax</h3>
<?php
print "This is an example of using PHP Default Syntax";
?>
</body></html>
• Script Syntax - Due to limitations with certain HTML editors, PHP added the ability to support a
mainstream delimiter variant, <script>. The following example demonstrates how this would
look:
<script language="php">
print "This is an example of using PHP script delimiting
syntax";
</script>
• Short Tags - Due to the fact that many programmers are interested in minimizing the amount of code
that needs to be written to accomplish a task, PHP implemented a shorter delimiter syntax to support
this desire. Instead of needing to type <?php to start the PHP script, programmers can simply type
<? to start the PHP script. The following example demonstrates how this would look:
<?
print "This is an example of using PHP Short Tag Syntax";
?>
• ASP-Style - There are many PHP programmers that have experience with other similar programming
languages, such as ASP. ASP delimits code using <% and %>. PHP has provided support for this
type of delimiting. The following example demonstrates how this would look:
<%
print "This is an example of using ASP-Style delimiting syntax";
%>
Thank for sharing this useful information about PHP. It is very helpful article.
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