Basic PHP Syntax

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Like ASP, PHP uses what I call "open-close bracket" syntax. In a classic ASP program, the syntax starts with an open bracket ( <% ) and ends with a close bracket ( %> ):

 <%  Response.write("A classic ASP program")  %> 

Much the same is done in PHP. The open-close bracket syntax starts with

<?php and ends with ?> :

 <?php  print("A PHP program");  ?> 

PHP also allows a style of syntax that is familiar to client-side script developers. This style of syntax starts with <SCRIPT LANGUAGE="php"> and ends with </SCRIPT> :

 <SCRIPT LANGUAGE="php">  print("test");  </SCRIPT> 

If you have a background in ASP, never fear. PHP also lets you use ASP-style open-close bracket syntax:

 <%  print("A PHP program")  %> 

However, for this style of open-close bracket syntax to work, you must edit the php.ini file:

 asp_tags = On 

This is set to Off by default.

Multiline Programs

Multiline PHP programs have additional syntax:

 <?php  print("This is your first");  print(" PHP Program");  ?> 

Note that PHP requires an end-of-line character ”the semicolon (;). If you run the program with no end-of-line character, as in the following code, you will receive a Parse error message:

 <?php  print("This is your first")  print(" PHP Program")  ?> 

If you have never used end-of-line characters , they can often trip you up. If you receive a Parse error message when writing your web applications, check for an end-of-line character at the line number given in the error message, as shown in Figure 3.1.

Figure 3.1. A Parse error message.

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