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 $highlight is true, then the output will be:
<html><body>
<p class="highlight">This is a paragraph.</p>
</body></html>
Otherwise, it will be:
<html><body>
<p>This is a paragraph.</p>
</body></html>
Using this method, you can have HTML tags with optional attributes, depending on some PHP condition. Extremely flexible and useful!
Escapando o HTML
Tudo o que estiver fora das tags PHP é ignorado pelo interpretador, o que permite arquivos PHP de conteúdo misto. Permite que o PHP seja incluído dentro de documentos HTML, para, por exemplo, a criação de templates.
<p>Isto vai ser ignorado pelo PHP e exibido pelo navegador.</p>
<?php echo 'Enquanto isto vai ser interpretado.'; ?>
<p>Isto também vai ser ignorado pelo PHP e exibido no navegador.</p>
Utilizando estruturas avançadas
Exemplo #1 Escape avançado usando condições
<?php if ($expression == true): ?>
Isto irá aparecer se a expressão for verdadeira.
<?php else: ?>
Senão isso que aparecerá.
<?php endif; ?>
Para impressão de grandes blocos de texto, sair do modo de interpretação do PHP é geralmente mais eficiente que enviar todo o texto através das funções echo ou print.
Nota:
Se o PHP for incluído no XML ou XHTML, as tags normais
<?php ?>precisam ser utilizadas para que o documento permaneca conformante aos padrões desses documentos.
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User Contributed Notes 12 notes
quickfur at quickfur dot ath dot cx ¶
13 years ago
ravenswd at gmail dot com ¶
14 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!
davidhcefx ¶
3 years ago
When the PHP interpreter hits the ?> closing tags, it WON'T output right away if it's inside of a conditional statement:
(no matter if it's an Alternative Syntax or not)
<html>
<?php
$a = 1;
$b = 2;
if ($a === 1) {
if ($b == 2) {
?><head></head><?php
} else {
?><body></body><?php
}
}
?>
</html>
This would output `<html><head></head></html>`.
Aside from conditional statements, the PHP interpreter also skip over functions! What a surprise!
<html>
<?php
function show($a) {
?>
<a href="https://www.<?php echo $a ?>.com">
Link
</a>
<?php
}
?>
<body>
<?php show("google") ?>
</body>
</html>
This gives `<html><body><a href="https://www.google.com">Link</a></body></html>`.
These really confused me, because at first I thought it would output any HTML code right away, except for Alternative Syntaxes (https://www.php.net/manual/en/control-structures.alternative-syntax.php). There are more strange cases than I thought.
snor_007 at hotmail dot com ¶
14 years ago
Playing around with different open and close tags I discovered you can actually mix different style open/close tags
some examples
<%
//your php code here
?>
or
<script language="php">
//php code here
%>
anisgazig at gmail dot com ¶
4 years ago
Version of 7.0.0,3 tags are available in php.
1.long form tag (<?php ?>)
2.short echo tag(<?= ?>)
3.short_open_tag(? ?)
You can use short_open_tag when you start xml with php.
coder at fishlet dot com ¶
3 years ago
I find the notion that PHP "starts parsing" inside a <?php ... ?> tag, and "just passes through" everything outside a tag, to be a confusing oversimplification and generally wrong.
For example, this code would be inexplicable:
<?php for ($i = 0; $i < 10; $i++) { ?>
Repeated<br>
<?php } ?>
I think a better way to look at it is that the PHP parser turns any text NOT inside a <?php ... ?> tag into an implicit echo statement that is embedded at the corresponding place in the code.
Anonymous ¶
3 years ago
Since it's not documented (AFAICT) and it might cause confusion: a single line break immediately after ?> is ignored. Since whitespace is hard to see, whitespace is replaced with _ and the following code
<?php echo '1'; ?>
<?php echo '2'; ?>_
<?php echo '3'; ?>
_<?php echo '4'; ?>_<?php echo '5'; ?>
will produce
12_
3_4_5
Emil Cataranciuc ¶
6 years ago
"<script language="php"> </script>, are always available." since PHP 7.0.0 is no longer true. These are removed along the ASP "<%, %>, <%=" tags.
mike at clove dot com ¶
13 years ago
It's possible to write code to create php escapes which can be processed later by substituting \x3f for '?' - as in echo "<\x3fphp echo 'foo'; \x3f>";
This is useful for creating a template parser which later is rendered by PHP.
anisgazig.com ¶
3 years ago
<p>This is ignore by the php parser and displayed by the browser </p>
<?php echo "While this is going to be parsed"; ?>
<?php
when php interpreter hits the closing tag it start to outputing everything whatever it finds until it hit another opening tag.If php interpreter find a conditional statement in the middle of a block then php interpreter decided which block skip
Advanced escaping using conditions
<?php $a = 10; if($a<100): ?>
This conditional block is executed
<?php else: ?>
otherwise this will be executed
<?php endif; ?>
In php 5 version,there are 5 opening and closing tags.
1.<?php echo "standard long form php tag and if you use xml with php this tag will be use";?>
2.<?= "short echo tag and alwayes available from 5.4.0";?>
3.<? echo "short open tag which is available if short_open_tag is enable in php ini configuration file directive or php was configured with --enable-short-tags.This tag has discoursed from php 7.If you want to use xml with php,then short_open_tag in php ini will be disabled";?>
4.<script language="php">
echo "Some editor do not like processing the code within this tag and this tag is removed from php 7.0.0 version";
</script>
5.<% echo "asp style tag and asp_tags should be enabled but now php 7.0.0 version,this tag is removed";%>
admin at furutsuzeru dot net ¶
15 years ago
These methods are just messy. Short-opening tags and ASP-styled tags are not always enabled on servers. The <script language="php"></script> alternative is just out there. You should just use the traditional tag opening:
<?php?>
Coding islands, for example:
<?php
$me = 'Pyornide';
?>
<?=$me;?> is happy.
<?php
$me = strtoupper($me);
?>
<?=$me;?> is happier.
Lead to something along the lines of messy code. Writing your application like this can just prove to be more of an
inconvenience when it comes to maintenance.
If you have to deal chunks of HTML, then consider having a templating system do the job for you. It is a poor idea to rely on the coding islands method as a template system in any way, and for reasons listed above.
