The php language supports several comment styles

php language supports 3 comment styles: 1. C style, using the "//" symbol and the syntax "//comment content"; 2. C language style, using the "/* */" symbol and the syntax "/* Comment content */"; 3. Shell style (Perl style), using the "#" symbol and the syntax "#Comment content".

The operating environment of this tutorial: windows7 system, PHP version 8.1, DELL G3 computer

PHP supports 3 comment styles: C, C and Unix Shell style (Perl style)

① Single-line comment (C style), symbol: //

②Multi-line comment (C style), symbol: /* */

③Special single-line comments (not commonly used, Shell style), symbol:

#1. C-style (//) comments

This kind of comment cannot appear ?> mark. If the short_open and asp_tag settings are turned on, &gt ; and %> also cannot appear in comments

<?php
echo "单行注释" ;//一般在代码右边少量说明或写在代码前面使之失效
?>

2. C language style (/* */), nested comments are not allowed

<?php
echo "多行注释" ;
echo "多行注释" ;
/*
一般说明脚本的相关信息，如版本，版权，作者日期等
使一长段代码失效
*/
?>

C-style comments will end when encountering the first "*/", so multi-line comments cannot be nested, otherwise a syntax error will be reported.

3. Shell style (#), same as C ban

<?php
echo "单行注释" ;#一般在代码右边少量说明或写在代码前面使之失效
?>

The three comment styles are as follows

Note: Single-line comments are only commented to the end of the line or the current PHP code block ("?>" at the end of the line will not be commented, and PHP encounters "?> " will jump out of PHP mode, and then parse HTML code or other)

Recommended learning: "PHP Video Tutorial"

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