PHP is the world's most widely used back-end programming language for the web - it runs server-side and can be used to perform all sorts of calculations, determine permissions, generate HTML output, query database tables, and much more.
I've been using PHP myself since 2003 and taught myself via learning-by-doing. At that time, I wanted to offer a free subdomain service for my company, but there was no viable solution at the time - so I developed it myself and reached thousands of users along the way, who I was able to do a favor for with this service.
In the meantime I have developed my own framework - this is a basic skeleton that contains many basic functionalities and serves as a basis for new websites as well as for CLI projects. CLI projects are applications that are executed purely on the server side and cannot be accessed directly via the browser. And there you get a glimpse of what you can actually do with PHP - much more than just websites.
In my framework, I put emphasis on the maximum possible security as well as on using as little server resources as possible - the latter is also called "light-weight".
To give an example regarding security: my framework contains among other things a function library for database access. After a few years, an internet-wide problem slowly became apparent: so-called SQL injections. This means that an SQL query could be manipulated via appropriately prepared user data in such a way that one could gain full access to the respective SQL database and change or even delete it. Long before "SQL injection" was established as a term, I had already fixed this attack vector in the database function library of my framework, because I am already so paranoid with every user input during programming that such security problems are never possible in the first place.
In addition, PHP has massively improved its performance since v7.0 - since v8.0, it even includes a JustInTime compiler, so that a script interpreter is no longer necessary, but instead efficient machine code is being executed.
I've been using PHP myself since 2003 and taught myself via learning-by-doing. At that time, I wanted to offer a free subdomain service for my company, but there was no viable solution at the time - so I developed it myself and reached thousands of users along the way, who I was able to do a favor for with this service.
In the meantime I have developed my own framework - this is a basic skeleton that contains many basic functionalities and serves as a basis for new websites as well as for CLI projects. CLI projects are applications that are executed purely on the server side and cannot be accessed directly via the browser. And there you get a glimpse of what you can actually do with PHP - much more than just websites.
In my framework, I put emphasis on the maximum possible security as well as on using as little server resources as possible - the latter is also called "light-weight".
To give an example regarding security: my framework contains among other things a function library for database access. After a few years, an internet-wide problem slowly became apparent: so-called SQL injections. This means that an SQL query could be manipulated via appropriately prepared user data in such a way that one could gain full access to the respective SQL database and change or even delete it. Long before "SQL injection" was established as a term, I had already fixed this attack vector in the database function library of my framework, because I am already so paranoid with every user input during programming that such security problems are never possible in the first place.
In addition, PHP has massively improved its performance since v7.0 - since v8.0, it even includes a JustInTime compiler, so that a script interpreter is no longer necessary, but instead efficient machine code is being executed.