Never had a dream come true Introductory tutorial from PHPNET

PHP is a tool for creating dynamic web pages. A web page with embedded PHP code is just like an ordinary HTML file, and you can edit it using any editor you like. This tutorial is for PHP 3.0.
What do I need? In this tutorial, we assume that your server already supports PHP and that all files have a .php3 extension. On most servers, this is the default extension for PHP files, you can check with your administrator. If your server supports PHP, this is enough. It's simple, create your PHP file and put it on your server, and the server will handle it smartly. This requires no compilation or installation of any additional tools. You can think of it this way: PHP files are regular HTML files with a new set of clever tags added.
Your first PHP code The colors in the above code are just to give you a visual aid, making it easier for you to understand the different parts of PHP tags and expressions. Please note that unlike CGI programs, executable permissions are not required. You can think of a PHP file as an HTML file containing a set of special tags that can do any number of things you're interested in.
　This program is very simple, you don’t need to create a WEB page specifically for this. All it does is display: Hello World.
If you try this code and it outputs nothing, the problem may be that your server does not support PHP. Please ask your administrator to confirm.
　The focus of the previous example is to introduce you to PHP tags. Use the "" tag. As shown in the example, you can freely enter and exit PHP mode in HTML files.
Some useful stuff Let’s do something more meaningful. If we want to check what the user's browser is, we can check the user agent (User Agent) string sent by the browser to the WEB server. This information is stored in a variable named $HTTP_USER_AGNET. The value of this variable can be easily displayed by using the following statement:
If the user is using Internet Explorer, then The displayed results may be: Mozilla/4.0 (compatible; MSIE 4.0; Windows 98) In fact, the user's browser also delivers a lot of other content. You can get a complete list of these variables with the following code:
Save this code into a file, say info.php3, and upload it to your server , open it with a browser, and you will see a lot of things that will surprise you. You can place multiple PHP statements within a set of PHP tags, or use a single block of code to do more. For example: If we want to check whether the browser is MSIE, we can use the following code:
{
　echo "You are using Internet Explorer.< ;br>";
}
?> Here we will introduce some new things. First is the "if" statement. If you are familiar with the basic syntax of C language, then you will easily understand this code. If you are not familiar with it, it is recommended to find some related books for reference. PHP retains the simple syntax of C and avoids the difficult-to-control string and memory processing in C language.
　Second, we called a function: strstr(). strstr() is a built-in function in PHP, used to find another string in a string. In the example, we search for "MSIE" in the variable $HTTP_USER_AGENT. If the font string is found, then the function returns a true value, that is, TRUE , otherwise vice versa.
Let’s take a look at how to enter and exit PHP mode, even in the middle of a PHP code block:
if (strstr($HTTP_USER_AGENT,"MSIE")){
?>
You are using Internet Explorer
}else{
?>

You are not using Internet Explorer
}?>
Use the method of jumping out of PHP mode and outputting HTML code directly instead of using the echo statement to output the results. It is very important to not destroy the logical integrity of the PHP code. The result displayed by running this code may be:
You are using Internet Explorer
Processing forms Another powerful place of PHP is processing forms in html files. You need to understand the basic concept that all HTML file form elements will automatically be sent to the target page with the same name. This seems a bit difficult to understand, let's illustrate this through the following example:

Your Name:
Your Age:

　This form only contains the necessary HTML tags and is not complete.When the user fills out this form and presses the "Submit" button, the file action.php3 is called. Suppose this file contains the following code:
Hi . You are years old.
　The effect of its execution is obvious, because the variable $ name and $age are automatically set by PHP.
More? This tutorial may be expanded, but that’s it for now.
　For other tutorials, please refer to:
WebMonkey
DevShed
phpTidbits
PHPBuider.com

The above has introduced the introductory tutorial of Never had a dream come true from PHPNET, including the content of Never had a dream come true. I hope it will be helpful to friends who are interested in PHP tutorials.