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.

Example #1 PHP Opening and Closing Tags

1.  <?php echo 'if you want to serve PHP code in XHTML or XML documents,
                use these tags'

2.  You can use the short echo tag to <?= 'print this string' ?>.
    It's equivalent to <?php echo 'print this string' ?>.

3.  <? echo 'this code is within short tags, but will only work '.
            'if short_open_tag is enabled'; ?>

Short tags (example three) are available by default but can be disabled either via the short_open_tag php.ini configuration file directive, or are disabled by default if PHP is built with the --disable-short-tags configuration.


As short tags can be disabled it is recommened to only use the normal tags (<?php ?> and <?= ?>) to maximise compatibility.

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.

echo "Hello world";

// ... more code

echo "Last statement";

// the script ends here with no PHP closing tag

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User Contributed Notes 3 notes

anisgazig at gmail dot com
4 months ago
When php parse a file,it looks for opening and closing tag.php parser interpreting  the code between opening and closing tag and allows php to be embedded in all shorts of different documents.Outside of opening and closing tag is ignored by the php parser.

Now php recommended you to use only two tags.

1.Standard tag which is <?php echo "I'm Standard tag"; ?>
2.Short echo tag which is <?= "I'm Short echo tag"; ?>

Both are not affected by php ini configuration file directive.

Although php also allow short open tag which is discoursed but still available if php was configured with --enable-short-tags or  short_open_tag is enabled in php ini configuration file directive.

if you want to use php in combination with xml,you can disable short_open_tag in order to use <?xml ?> inline.
Otherwise, you can print it with PHP, for example: <?php echo '<?xml version="1.0"?>'; ?>

short_echo_tag also affected the short echo tag before 5.4.0
since 5.4.0,short echo tag is always available.

asp tag <% %> and <%= > are removed from php 7
script tag <script language="php"> <script/> also removed from php 7

It is preferable to omit the closing tag if a file only contain the php code.
<?php echo "a statement";
"another statement";

It prevent unwanted whitespace or new line being added after the closing tag.
3 months ago
این توضیح فارسی است || this note is persian

برای شروع کد زدن پی اچ پی از تگ
<?php   ?>
استفاده میکنیم

تگ فوق استاندارد است

همچنین میتوانیم از
<? ?>
استفاده کنیم که درون کد های اچ تی ام ال کاربرد وسیع دارد

همچنین میتوانیم از تگ
<!  !>
استفاده کنیم که باید در قسمت کانفیگ آپاچی آن را ست کنیم که البته توصیه نمیشود.
crazytonyi at gmail dot com
4 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 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 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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