PHP script start with the <?php tag and ends with ?> tag. Between the two tags, a PHP script is written. <?php the opening tag and the ?> closing tag tells the engine to treat the enclosed code block as PHP code, rather than simple HTML.
<?php // opening tag echo "Hello, world!"; // executable block ?> // closing tag
Read also: How to install xampp in windows 10
Embedding PHP within HTML
.php extension is used as the file name suffix. Inside a PHP file you can write regular HTML code. But ensure that all php codes are enclosed between <?php and ?> tags.
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>A Simple PHP File</title> </head> <body> <h1><?php echo "Hello, world!"; ?></h1> </body> </html>
Hope you understand the above code.
PHP support single-line and also multi-line comments. To write a single-line comment either start the line with either two slashes // or a hash symbol #. For example:
<?php // This is a single line comment # This is also a single line comment echo "Hello, world!"; ?>
To write multi-line comments, start the comment with a slash followed by an asterisk /* and end the comment with an asterisk followed by a slash */, like this:
<?php /* This is a multiple line comment section that spans across more than one line */ echo "Hello, world!"; ?>
Case Sensitivity in PHP
PHP is case sensitive language means $number and $NUMBER are treated as two different variables.
<?php $number = 10; //assign 10 to the $number variable // Print The Value echo $number; //OUTPUT: 10 echo $NUMBER; //OUTPUT: Undefined Varibale warning for $NUMBER ?>
Hope you got it!