When the documentation says that the PHP parser ignores everything outside the <?php ... ?> tags, it means literally EVERYTHING. Including things you normally wouldn't consider "valid", such as the following:
<html><body>
<p<?php if ($highlight): ?> class="highlight"<?php endif;?>>This is a paragraph.</p>
</body></html>
Notice how the PHP code is embedded in the middle of an HTML opening tag. The PHP parser doesn't care that it's in the middle of an opening tag, and doesn't require that it be closed. It also doesn't care that after the closing ?> tag is the end of the HTML opening tag. So, if $highlight is true, then the output will be:
<html><body>
<p class="highlight">This is a paragraph.</p>
</body></html>
Otherwise, it will be:
<html><body>
<p>This is a paragraph.</p>
</body></html>
Using this method, you can have HTML tags with optional attributes, depending on some PHP condition. Extremely flexible and useful!
Den HTML-Bereich verlassen
Alles außerhalb eines Paares von öffnenden und schließenden Tags wird vom PHP-Parser ignoriert, was es ermöglicht, dass PHP-Dateien gemischten Inhalt haben können. Dadurch kann PHP in HTML-Dokumente eingebettet werden, zum Beispiel um Templates zu erstellen.
<p>Das hier wird von PHP ignoriert, und vom Browser angezeigt.</p>
<?php echo 'Wohingegen das hier geparst wird.'; ?>
<p>Dies wird ebenfalls von PHP ignoriert, und vom Browser angezeigt.</p>Verwendung von Strukturen mit Bedingungen
Beispiel #1 Fortgeschrittene Ausgabe unter Verwendung von Bedingungen
<?php if ($expression == true): ?>
Dies wird angezeigt, wenn der Ausdruck wahr ist.
<?php else: ?>
Andernfalls wird dies angezeigt.
<?php endif; ?>Für die Ausgabe von großen Textblöcken ist der Ausstieg aus dem Parse-Modus generell effizienter, als den gesamten Text durch echo oder print zu jagen.
Hinweis:
Wenn PHP in XML oder XHTML eingebettet wird, müssen die normalen
<?php ?>-PHP-Tags verwenden werden, um die Standards einzuhalten.
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User Contributed Notes 4 notes
quickfur at quickfur dot ath dot cx ¶
14 years ago
ravenswd at gmail dot com ¶
15 years ago
One aspect of PHP that you need to be careful of, is that ?> will drop you out of PHP code and into HTML even if it appears inside a // comment. (This does not apply to /* */ comments.) This can lead to unexpected results. For example, take this line:
<?php
$file_contents = '<?php die(); ?>' . "\n";
?>
If you try to remove it by turning it into a comment, you get this:
<?php
// $file_contents = '<?php die(); ?>' . "\n";
?>
Which results in ' . "\n"; (and whatever is in the lines following it) to be output to your HTML page.
The cure is to either comment it out using /* */ tags, or re-write the line as:
<?php
$file_contents = '<' . '?php die(); ?' . '>' . "\n";
?>
sgurukrupa at gmail dot com ¶
10 years ago
Although not specifically pointed out in the main text, escaping from HTML also applies to other control statements:
<?php for ($i = 0; $i < 5; ++$i): ?>
Hello, there!
<?php endfor; ?>
When the above code snippet is executed we get the following output:
Hello, there!
Hello, there!
Hello, there!
Hello, there!
gazianis005 at gmail dot com ¶
1 year ago
There are two types of escaping from HTML.
1.Normal escaping of using outside of a pair of opening and closing tag
2.Advance escaping of using conditions.
Example of normal escaping
<p>This is going to be ignored by the php parser and displayed by the browser</p>
<?php echo 'This is going to be parsed';?>
<>This will also ignored by the php parser and displayed by the browser</>
Example of advanced escaping
<?php if($expression == true): ?>
This will show if expression is true
<?php else : ?>
Otherwise this will show
<?php endif ;?>
