PHP newbies on the road (3)_PHP tutorial

Learn PHP from a simple program

The PHP site’s online tutorials are already great. This part of the article will make you familiar with PHP. It is impossible for me to miss anything, my purpose is only to allow you to quickly start your PHP programming.

3.1 First Conditions

You must first have a working web server that supports PHP. I assume that all PHP files on your server have the extension .php3.

3.2 Installation of PHP

For the installation and configuration of PHP, you can check the "Complete PHP Installation Guide" special article on Taoba website.

3.3 Syntax

From a syntax perspective, PHP language is similar to C language. It can be said that PHP draws on the grammatical features of C language and is improved from C language. We can mix PHP code and HTML code. Not only can we embed PHP scripts into HTML files, we can even embed HTML tags in PHP scripts. Here are a few approaches you can take. You can choose whichever one works best for you and stick with it!

Separate from HTML

Here are the methods you can use:



<% . . . %>

　Note: When you use "" When embedding PHP code in an HTML file, it may conflict with XML. At the same time, whether you can use this shortened form depends on the settings of PHP itself. To make your PHP code adaptable to XML and other editors, you can make your PHP code adaptable to XML parsers by adding "php" after the opening question mark. For example: "". You can also use script tags like other script languages, such as: "".


Statement

Like Perl and C, statements are separated by ";" in PHP. Those separate tags from HTML also indicate the end of a statement.

Comments

PHP supports C, C++ and Unix style comments:

/* C, C++ style multi-line comments*/
// C++ style single line Comments
# Unix style single-line comments

echo and print

The simplest interaction between PHP and HTML is achieved through the print and echo statements. In actual use, print and echo are both The functions are almost identical. It can be said that wherever one can be used, the other can also be used. However, there is still a very important difference between the two: in the echo function, multiple strings can be output at the same time, while in the print function, only one string can be output at the same time. At the same time, the echo function does not require parentheses, so the echo function is more like a statement than a function. Let's take a look at the following example:

$a="hello";
$b="world";
echo "a","b" ;
print "a","b";
?>

After viewing the operation of this code in a browser, you will see the following results:
aba
Parse error: parse error in d:adminmyphphometest.php3 on line 5
This shows that this code cannot be completely interpreted. The error occurs in the fifth line of the code: "print "a","b ";".

3.4 A simple example

With the knowledge we have learned, you can write the simplest program to output a word that is perhaps the most famous word in the programming world


< /HEAD>

First PHP page

---

// Single line C++ style comment
/*
printing the message
*/
echo "Hello World!";
# Unix style single line comment
?>
< /BODY>

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