What is php? What is it used for?

PHP (foreign name: PHP: Hypertext Preprocessor, Chinese name: "Hypertext Preprocessor") is a general open source scripting language. The syntax absorbs the characteristics of C language, Java and Perl, which is easy to learn and widely used. It is mainly suitable for the field of Web development. PHP's unique syntax mixes C, Java, Perl, and PHP's own syntax. It can execute dynamic web pages faster than CGI or Perl. Compared with other programming languages, dynamic pages made with PHP embed programs into HTML (an application under the Standard Universal Markup Language) document for execution, and the execution efficiency is much higher than CGI that completely generates HTML tags; PHP can also execute compiled code. Compilation can achieve encryption and optimize code running, making the code run faster. It can be embedded into HTML and is especially suitable for web development.

The above is a simple answer, but what does it mean? Please look at the following example:

Please note the difference between this example and other scripts written in C or Perl language - unlike using a large number of commands to write a program to output HTML, the PHP page is HTML, but with some code embedded in it to do something (in this case outputting "Hi, I'm a PHP script!"). PHP code is enclosed in special start and end characters , making it possible to enter and exit "PHP mode".

Different from client-side JavaScript, PHP code runs on the server side. If you build code similar to the example above on the server, after running the script, the client will receive the results, but they will have no way of knowing how the code behind it works. You can even set up the web server to let PHP handle all HTML files, so the user has no way of knowing what the server is doing.

One of the great benefits of using PHP is that it is extremely simple for beginners, while also providing a variety of advanced features for professional programmers. Don’t be afraid when you see PHP’s long list of features. You can get started quickly, and you can write some simple scripts in just a few hours.

Although PHP is developed for the purpose of server-side scripting, in fact its functions are far from limited to this.

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