The main difference between GET and POST is how the form data is passing. Both are used for passing form field values. All the values which is submitted by the GET method will be appended to the URL.Where as POST method send the data with out appending the URL(hidden) In GET Method we can bookmark the URLs where as in POST method its not possible In GET Method there is a limit for passing the data from one page to another(ie 256 characters according to w3c standards)But in POST we can send large amount of data <?php session_start(); $_SESSION["var"] = NULL; echo $var = "www.w3answers.com"; ?> The output : www.w3answers.com and warning as below Warning: Unknown: Your script possibly relies on a session side-effect which existed until PHP 4.2.3. Please be advised that the session extension does not consider global variables as a ....! It Makes the MySQL engine refuse UPDATE and DELETE commands where the WHERE clause is not present. ....! When a user first encounters a page in your application that call ssession start(),a sessionis created for the user.PHP generates a random session identifier to identify the user,and then it sends a set-Cookieheader to the client.By default,the name of this cookie is PHPSESSID,but it is possible to change the cookiename in php.ini or by using the session name() function.On subsequent visits,the client identifies the user with the cookie,and this is how thea application maintains state. <? $string = 'APPLE'; echo stristr($string, 97); ?> a) Error b) APPLE c) Apple d) None of the above ANS : APPLE ....! include() The include() statement includes and evaluates the specified file. This also applies to require(). The two constructs are identical in every way except how they handle failure. include() produces a Warning while require() results in a Fatal Error. In other words, use require() if you want a missing file to halt processing of the page. include() does not behave this way, the script will continue regardless. include_once() The include_once() statement includes and evaluates the specified file during the execution ....! $stringOfText = "<p>This is a test</p>"; $expression = "/<(.*?)>(.*?)<\/(.*?)>/"; echo preg_replace($expression, "\\2", $stringOfText); ....! 1. fget(); 2. file_open(); 3. fopen(); 4. open_file(); ANS:fopen(); ....! We can use a simple JavaScript code linked to an event trigger of any form field. In the JavaScript code, we can call the document.form.submit() function to submit the form ....! MySQL Engines MyISAM HEAP MEMORY MERGE MRG_MYISAM ISAM MRG_ISAM InnoDB INNOBASE BDB BERKELEYDB NDBCLUSTER NDB EXAMPLE ARCHIVE CSV   ....! According to PHP official manual   It is used to converts a string to an array. If the optional split_length parameter is specified, the returned array will be broken down into chunks with each being split_length in length, otherwise each chunk will be one character in length. FALSE is returned if split_length is less than 1 a) Solid & oracle b) mysql c) None of the above d) All of the above All of the above ....! <?php $banned = array("24.91.102.173", "64.21.162.113"); if (in_array($_SERVER['REMOTE_ADDR'], $banned)) { echo "You have been banned."; exit; } ?>   ....! <?php ob_start(); // start an output buffer echo ‘This text is from the w3answers buffer*******<br />’; // output that will be stored in the buffer $w3buffer = ob_get_contents(); // store buffer content in $w3buffer variable ob_end_clean(); // stop and clean the output buffer echo ‘This is not from the w3answers buffer!!!!!!!!<br />’; echo $w3buffer; ?> O/p MySQL (pronounced "my ess cue el") is an open source relational database management system (RDBMS) that uses Structured Query Language (SQL), the most popular language for adding, accessing, and processing data in a database. Because it is open source, anyone can download MySQL and tailor it to their needs in accordance with the general public license. MySQL is noted mainly for its speed, reliability, and flexibility