Driving skills for newbies on the road PHP newbies on the road (3)

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's 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 special article "Complete PHP Installation Guide" on Taoba website.
3.3 Grammar
　 From a syntactic point of view, 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
The following are the methods that can be used:
. . . ?>

".
Statements
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
PHP and HTML are the simplest The interaction is achieved through print and echo statements. In actual use, the functions of print and echo are almost exactly the same. 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 watching the operation of this code with 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 does not It cannot be completely explained. 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