PHP: PHP tags - Manual

PHP tags

When PHP parses a file, it looks for opening and closing tags, which are <?php and ?> which tell PHP to start and stop interpreting the code between them. Parsing in this manner allows PHP to be embedded in all sorts of different documents, as everything outside of a pair of opening and closing tags is ignored by the PHP parser.

PHP includes a short echo tag <?= which is a short-hand to the more verbose <?php echo.

PHP also allows for short open tag <? (which is discouraged since it is only available if enabled using the short_open_tag php.ini configuration file directive, or if PHP was configured with the --enable-short-tags option).

If a file contains only PHP code, it is preferable to omit the PHP closing tag at the end of the file. This prevents accidental whitespace or new lines being added after the PHP closing tag, which may cause unwanted effects because PHP will start output buffering when there is no intention from the programmer to send any output at that point in the script.


<?php
echo "Hello world";

// ... more code

echo "Last statement";

// the script ends here with no PHP closing tag

**Changelog**
Version	Description
7.0.0	The ASP tags `<%`, `%>`, `<%=`, and the script tag `<script language="php">` are removed from PHP.
5.4.0	The tag <?= is always available regardless of the short_open_tag ini setting.

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User Contributed Notes 2 notes

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crazytonyi at gmail dot com ¶

3 years ago


Regarding earlier note by @purkrt :

> I would like to stress out that the opening tag is "<?php[whitespace]", not just "<?php"

This is absolutely correct, but the wording may confuse some developers less familiar with the extent of the term "[whitespace]".

Whitespace, in this context, would be any character that generated vertical or horizontal space, including tabs ( \t ), newlines ( \n ), and carriage returns ( \r ), as well as a space character ( \s ). So reusing purkrt's example:

<?php/*blah*/ echo "a"?> 

would not work, as mentioned, but :

<?php /*php followed by space*/ echo "a"?>

will work, as well as :

<?php
/*php followed by end-of-line*/ echo "a"?>

and :

<?php    /*php followed by tab*/ echo "a"?>

I just wanted to clarify this to prevent anyone from misreading purkrt's note to mean that a the opening tag --even when being on its own line--required a space ( \s ) character. The following would work but is not at all necessary or how the earlier comment should be interpreted :

<?php 
/*php followed by a space and end-of-line*/ echo "a"?>

The end-of-line character is whitespace, so it is all that you would need.

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-25

Mark Clements (kennel17.co.uk) ¶

1 year ago


Closing PHP tags are recognised within single-line comments:

    <?php
    // Code will end here ?> This is output as literal text.

    <?php
    # Same with this method of commenting ?> This is output as literal text.

However they do not have an effect in C-style comments:

    <?php
    /* Code will not end here ?> as closing tags are ignored inside C-style comments. */
    ?>

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