The scope of a variable is the context within which it is defined. For the most part, all PHP variables only have a single scope. This single scope spans included and required files as well.
Is it possible to submit a form with a dedicated button?
It is possible to use the document.form.submit() function to submit the form. For example: <input type=button value="SUBMIT" onClick="document.form.submit()">
What is the difference between ereg_replace() and eregi_replace()?
The function eregi_replace() is identical to the function ereg_replace() except that it ignores case distinction when matching alphabetic characters.
Is it possible to protect special characters in a query string?
Yes, we use the urlencode() function to be able to protect special characters.
What are the three classes of errors that can occur in PHP?
The three basic classes of errors are notices (non-critical), warnings (serious errors) and fatal errors (critical errors).
What is the difference between characters \034 and \x34?
\034 is octal 34 and \x34 is hex 34.
How can we pass the variable through the navigation between the pages?
It is possible to pass the variables between the PHP pages using sessions, cookies or hidden form fields.
Is it possible to extend the execution time of a PHP script?
The use of the set_time_limit(int seconds) enables us to extend the execution time of a PHP script. The default limit is 30 seconds.
Is it possible to destroy a cookie?
Yes, it is possible by setting the cookie with a past expiration time.
What is the default session time in PHP?
The default session time in php is until the closing of the browser
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Is it possible to use COM component in PHP?
Yes, it's possible to integrate (Distributed) Component Object Model components ((D)COM) in PHP scripts which is provided as a framework.
Explain whether it is possible to share a single instance of a Memcache between multiple PHP projects?
Yes, it is possible to share a single instance of Memcache between multiple projects. Memcache is a memory store space, and you can run memcache on one or more servers. You can also configure your client to speak to a particular set of instances. So, you can run two different Memcache processes on the same host and yet they are completely independent. Unless, if you have partitioned your data, then it becomes necessary to know from which instance to get the data from or to put into.
what the difference between the 'BITWISE AND' operator and the 'LOGICAL AND' operator?
$a and $b: TRUE if both $a and $b are TRUE.
$a & $b: Bits that are set in both $a and $b are set.
What are the two main string operators?
The first is the concatenation operator ('.'), which returns the concatenation of its right and left arguments. The second is ('.='), which appends the argument on the right to the argument on the left.
What does the array operator '===' means?
$a === $b TRUE if $a and $b have the same key/value pairs in the same order and of the same types.
What is the differences between $a != $b and $a !== $b?
!= means inequality (TRUE if $a is not equal to $b) and !== means non-identity (TRUE if $a is not identical to $b).
what is the definition of a session?
A session is a logical object enabling us to preserve temporary data across multiple PHP pages.
How to initiate a session in PHP?
The use of the function session_start() lets us activating a session.
How can you propagate a session id?
You can propagate a session id via cookies or URL parameters.
What is the meaning of a Persistent Cookie?
A persistent cookie is permanently stored in a cookie file on the browser's computer. By default, cookies are temporary and are erased if we close the browser.
When do sessions end?
Sessions automatically end when the PHP script finishes executing but can be manually ended using the session_write_close().
What is the difference between session_unregister() and session_unset()?
The session_unregister() function unregister a global variable from the current session and the session_unset() function frees all session variables.
What does $GLOBALS mean?
$GLOBALS is associative array including references to all variables which are currently defined in the global scope of the script.
What does $_SERVER mean?
$_SERVER is an array including information created by the web server such as paths, headers, and script locations.
What does $_FILES means?
$_FILES is an associative array composed of items sent to the current script via the HTTP POST method.
What is the difference between $_FILES['userfile']['name'] and $_FILES['userfile']['tmp_name']?
$_FILES['userfile']['name'] represents the original name of the file on the client machine,
$_FILES['userfile']['tmp_name'] represents the temporary filename of the file stored on the server.
How can we get the error when there is a problem to upload a file?
$_FILES['userfile']['error'] contains the error code associated with the uploaded file.
How can we change the maximum size of the files to be uploaded?
We can change the maximum size of files to be uploaded by changing upload_max_filesize in php.ini.
What does $_ENV mean?
$_ENV is an associative array of variables sent to the current PHP script via the environment method.
How can we determine whether a PHP variable is an instantiated object of a certain class?
To be able to verify whether a PHP variable is an instantiated object of a certain class we use instanceof.