What is PHP?
The PHP software works with the web server, which is the software that delivers web pages to the world. When you type a URL into your web browser’s address bar, you’re sending a message to the web server at that URL, asking it to send you an HTML file. The web server responds by sending the requested file. Your browser reads the HTML file and displays the web page.
You also request a file from the web server when you click a link in a web page. In addition, the web server processes a file when you click a web page button that submits a form. This process is essentially the same when PHP is installed. You request a file, the web server happens to be running PHP, and it sends HTML back to the browser, thanks to the programming in PHP.
More specifically, when PHP is installed, the web server is configured to expect certain file extensions to contain PHP language statements. Often the extension is .php or .phtml, but any extension can be used. When the web server gets a request for a file with the designated extension, it sends the HTML statements as is, but PHP statements are processed by the PHP software before they’re sent to the requester.
When PHP language statements are processed, only the output, or anything printed to the screen is sent by the web server to the web browser. The PHP language statements, those that don’t produce any output to the screen, aren’t included in the output sent to the browser, so the PHP code is not normally seen by the user.
For instance, in this simple PHP statement,
<?php the PHP opening tag ?>is the closing tag.
That regular HTML statement is delivered to the user’s browser. The browser interprets the statement as HTML code and displays a web page with one paragraph — Hello World. The PHP statement isn’t delivered to the browser, so the user never sees any PHP statements. PHP and the web server must work closely together.
PHP isn’t integrated with all web servers but does work with many of the popular web servers. PHP works well with the Apache web server. PHP also works with Microsoft Internet Information Services (IIS) and others.
8 June 1995was released in 1993 with the intention of sharing information which can be readable and accessible via web browsers. But not much of the developers were involved in creating websites. So the language was also not growing.
1 November 1997Officially called "PHP/FI 2.0". This is the first release that could actually be characterised as PHP, being a standalone language with many features that have endured to the present day. .
6 June 1998Development moves from one person to multiple developers. Zeev Suraski and Andi Gutmans rewrite the base for this version.
22 May 2000
Added more advanced two-stage parse/execute tag-parsing system called the Zend engine.
Introduced "superglobals" ($_GET, $_POST, $_SESSION, etc.).
Disabled register_globals by default. Data received over the network is not inserted directly into the global namespace anymore, closing possible security holes in applications.
Fixed a memory corruption bug, which required breaking binary compatibility with extensions compiled against PHP version 4.3.x.
13 July 2004
Zend Engine II with a new object model.Performance improvements with introduction of compiler variables in re-engineered PHP Engine. Added PHP Data Objects (PDO) as a consistent interface for accessing databases.
Enabled the filter extension by default. Native JSON support.
Namespace support; late static bindings, jump label (limited goto), closures, PHP archives (phar), garbage collection for circular references, improved Windows support, sqlite3, mysqlnd as a replacement for libmysql as underlying library for the extensions that work with MySQL, fileinfo as a replacement for mime_magic for better MIME support, the Internationalization extension, and deprecation of ereg extension.
Constant scalar expressions, variadic functions, argument unpacking, new exponentiation operator, extensions of the use statement for functions and constants, new phpdbg debugger as a SAPI module, and other smaller improvements
3 December 2015
Zend Engine 3 (performance improvements and 64-bit integer support on Windows), uniform variable syntax, AST-based compilation process, added Closure::call(), bitwise shift consistency across platforms, ?? (null coalesce) operator, Unicode code point escape syntax, return type declarations, scalar type (integer, float, string and boolean) declarations, <=> "spaceship" three-way comparison operator, generator delegation, anonymous classes, simpler and more consistently available CSPRNG API, replacement of many remaining internal PHP "errors" with the more modern exceptions, and shorthand syntax for importing multiple items from a namespace.
As stated early, languages never die, they proliferate. PHP is quite popular and widely used programming language, it won't fade easily. PHP usage will drop down in slow and steady manner. PHP is its own victim in some cases.