HTML and CSS Reference
In-Depth Information
The text that precedes
//
is processed by PHP, so the second line assigns the
$color
variable. On the third line, I've turned off the assignment by commenting it out. PHP
also supports multiple-line comments, which begin with
/*
and end with
*/
. If you want
to comment out several lines of code, you can do so like this:
/*
$color = 'red';
$count = 55; // Set the number of items on a page.
// $count = $count + 1;
*/
PHP ignores all the lines inside the comments. Note that you can put the
//
style com-
ment inside the multiline comment with no ill effects. You cannot, however, nest multi-
line comments. This is illegal:
/*
$color = 'red';
$count = 55; // Set the number of items on a page.
/* $count = $count + 1; */
*/
NOTE
The generally accepted style for PHP code is to use
//
for single-
line comments rather than
#
.
Variables
Variables just provide a way for the programmers to assign a name to a piece of data. In
PHP, these names are preceded by a dollar sign (
$
). Therefore, you might store a color in
a variable called
$color
or a date in a variable named
$last_published_at
. Here's how
you assign values to those variables:
$color = “red”;
$last_published_at = time();
The first line assigns the value
“red”
to
$color
; the second returns the value returned by
the built-in PHP function
time()
to
$last_published_at
. That function returns a time-
stamp represented as the number of seconds since the “UNIX epoch.”
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One thing you should notice here is that you don't have to indicate what kind of
item you'll be storing in a variable when you declare it. You can put a string in it,
as I did when I assigned
“red”
to
$color
. You can put a number in it, as I did with
$last_published_at
. I know that the number is a timestamp, but as far as PHP is
