PHP (Hypertext Preprocessor) is a widely-used open source scripting language especially suited for web development and can be embedded into HTML. Here are some basics of PHP syntax to get you started:

Basic PHP Syntax

1. PHP Tags:

   PHP tags are used to delineate PHP code within a file. These tags tell the server to interpret the enclosed code as PHP. Here are the different types of PHP tags you can use.

   Standard PHP Tags:

   The most common way to open and close PHP code:

   PHP

   <?php

   // Your PHP code goes here

   ?>

   Short-Open Tags:

   These tags are a shorter form but are not always enabled by default on all servers due to potential security issues. They can be enabled with the short_open_tag directive in the php.ini file:

   PHP

   <?

   // Your PHP code goes here

   ?>

   Echo Tags:

   A shorthand for '<?php echo' that directly outputs content:

   PHP

   <?= "Hello, World!"; ?>
   ASP Tags:

   These tags are similar to ASP style and are rarely used. They require the asp_tags directive to be enabled in the php.ini file (which is deprecated and removed in recent PHP versions):

   PHP

   <%

   // Your PHP code goes here

   %>
   Script Tags:

   Another rarely used method, similar to embedding JavaScript, and requires asp_tags to be enabled:

   PHP

   <script language="php">
// PHP code goes here
</script>

2. Echo Statement: Used to output text or variables.

   PHP

   <?php

   echo "Hello, World!" ;

   ?>

3. Variables.

   Variables in PHP start with a $ sign followed by the name of the variable.

   PHP

   <?php

   $greeting = "Hello,World!";

   echo $greeting ;

   ?>

4. Comments.

   Single-line comments:

   PHP

   <?php

   // This is a single-line comment
   echo "Hello, World!"; // This is also a single-line comment

   ?>

   Multi-line comments:

   PHP

   <?php

   /*
   This is a multi-line comment
   */
   echo "Hello, World!";

   ?>

5. Data Types:

   String:

   PHP

   <?php

   $String= "Hello,World!";

   echo $String ;

   ?>

   Integer:

   PHP

   <?php

   $int = 42;

   echo $int ;

   ?>

   Float:

   PHP

   <?php

   $float = 3.14;

   echo $float ;

   ?>

   Boolean:

   PHP

   <?php

   $bool = true;

   echo $bool ;

   ?>

6. Arrays:

   Indexed array:

   PHP

   <?php

   $colors = array("Red", "Green", "Blue");

   echo $colors[0]; // Outputs "Red"

   ?>

   Associative array:

   PHP

   <?php

   $ages= array("Peter" => 35, "Ben" => 37, "Joe" => 43);

   echo $ages["Peter" ]; // Outputs 35

   ?>

7. Conditional Statements:

   If statement:

   PHP

   <?php

   $x = 10 ;

   if ($x > 5) {

   echo "x is greater than 5";

   }

   ?>

   If-else statement:

   PHP

   <?php

   $x = 10 ;

   if ($x > 5) {

   echo "x is greater than 5";

   } else{

   echo "x is not greater than 5";

   }

   ?>

   Elseif statement:

   PHP

   <?php

   $x = 10 ;

   if ($x > 5) {

   echo "x is greater than 5";

   } elseif ($x == 5){

   echo "x is equal to 5";

   } else{

   echo "x is not greater than 5";

   }

   ?>

8. Loops:

   While loop:

   PHP

   <?php

   $x = 1 ;

   while ($x <=5) {

   echo "The number is: $x <br>";

   }

   ?>

   For loop:

   PHP

   <?php

   for( $x = 0; $x <= 10; $x++) {

   echo "The number is: $x <br>";

   }

   ?>

   Foreach loop:

   PHP

   <?php

   $colors = array( "Red", "Green", "Blue");

   foreach ($colors as $value) {

   echo "$value <br>";

   }

   ?>

9. Functions:

   PHP

   <?php

   function writeMessage() {

   echo "Hello, World!";

   }

   writeMessage(); // Calls the function

   ?>

10. Superglobals:

    $_GET, $_POST, $_SERVER, $_SESSION, $_COOKIE, $_FILES, $_REQUEST, $_ENV

    PHP

    <?php

    echo $_SERVER['PHP_SELF']; // Outputs the filename of the currently executing script

    ?>

php
<?php
        // Define variables
        $name = "John Doe";
        $age = 30;
        $is_student = true;
    
        // Function to display greeting
        function displayGreeting($name) {
            echo "Hello, $name!";
        }
    
        // Check age and display appropriate message
        if ($age > 18) {
            echo "You are an adult.<br>";
        } else {
            echo "You are a minor.<br>";
        }
    
        // Loop through an array of colors
        $colors = array("Red", "Green", "Blue");
        foreach ($colors as $color) {
            echo "Color: $color <br>";
        }
    
        // Call the function
        displayGreeting($name);
    ?>