New lines placed after PHP closing tags are ignored;
<?= "A"?>
B
<?= "C"?>
Output:
AB
C
New lines placed after PHP closing tags are ignored;
<?= "A"?>
B
<?= "C"?>
Output:
AB
C
Omit closing tag ?> always whenever you can
example:
<!DOCTYPE html><head>
<title><?php include'varia.php'; echo$title?></title>
</head><body></body></html>
varia.php
<?php
$title = 'Welcome';
?>
[new line] //other words: an extra 'Enter' is guilty
---------------
and you get:
?Welcome - at the browser label
source won't tell you what happened - there will be fine:
<!DOCTYPE html><head>
<title>Welcome</title>
</head><body></body></html>
Now imagine, what else can go wrong because of it? Everything, as Murphy said.
And you will look for the answer why...? And where...?
It's just simplest example.
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. */
?>
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.