empty ($_POST[ 'user' ])) { $query = mysql_query ( "SELECT * FROM UserName where userName = ' $_POST[user] ' AND pass = ' $_POST[pass] '" ) or die ( mysql_error ()); $row = mysql_fetch_array ($query) or die ( mysql_error ()); if ( ! This PHP code is telling the PHP CGI to take the value submitted by the user’s browser, stored in $_POST[user] and pass it to the MySQL context using the mysql_query() function.