What is the difference between mysql_connect and mysql_pconnect? 

The mail() function allows you to send emails directly from a script.

PHP’s configuration file is called php.ini.

$filename = "/home/user/guest/newfile.txt";
$file = fopen( $filename, "w" );
if( $file == false )
{
echo ( "Error in opening new file" );
exit();

}
fwrite( $file, "This is a simple test\n" );
fclose( $file );

The principle distinction amongst sessions and cookies is that sessions are put away on the server, and cookies are put away on the client's PCs in the content record position. Cookies can not hold various variables,But Session can hold numerous variables.We can set expiry for a cookie,The session just stays dynamic the length of the program is open.Users don't have admittance to the information you put away in Session,Since it is put away in the server. Session is mostly utilized for login/logout reason while cookies utilizing for client movement following.

The PHP default variable $_PHP_SELF is utilized for the PHP script name and when you click "submit" catch then same PHP script will be called.

We can send 1024 bytes utilizing GET() yet POST() can exchange extensive measure of information and POST is the protected strategy than GET technique .

These two methods are bulid-in methods  in php. with  construct() we can overwride the parent class method. The inverse of the __construct() PHP capacity while making another class, is the __destruct() technique. The __destruct() technique will consequently keep running, after you've completed with the PHP class.

Notify URL and Return URL is used in Paypal Payment Gateway integration. Notify URL is used by PayPal to post information about the transaction. Return URL is used by the browser; A url where the user needs to be redirected on completion of the payment process.