English
English
PHP is a server-side scripting language. When a web page containing PHP code is requested, the web server starts the PHP interpreter, loads and parses the PHP code, executes the instructions, and finally generates a response to return to the browser. Below are the steps of PHP function execution on the server:
The web server first receives the HTTP request from the browser and determines that the requested page contains PHP code.
The web server starts the PHP interpreter, which is responsible for parsing and executing the PHP code.
The PHP interpreter loads the script containing PHP code and parses it into source code instructions.
These source code instructions are compiled into an intermediate code (opcode). This opcode is an optimized machine instruction that can be executed more efficiently.
The web server’s virtual machine executes the opcode and performs the corresponding operations based on the compiled instructions.
The PHP interpreter generates a response containing the result, such as HTML code or other data, ready to be sent back to the browser.
The web server sends the response generated by the PHP interpreter back to the browser, which then renders the response to the user.
Next, let’s look at a simple PHP script that calculates the sum of two numbers on the server side and outputs the result:
<?php // Receive numbers from the form submission $num1 = $_POST['num1']; $num2 = $_POST['num2']; // Calculate the sum $sum = $num1 + $num2; // Output the result echo "The sum is: $sum"; ?>
When the user submits a form containing this script, the web server will start the PHP interpreter, load and parse the script, read the num1 and num2 values from the form, calculate the sum, generate a response, and finally send the result back to the browser.
Thus, the execution of PHP functions on the server side is essentially about transforming PHP code into a series of instructions, executing these instructions on the server, and generating a response to be returned to the user.
