Array is a data type which has multiple values in single variable.
< ?php
\(\$\)children = array ("SriAkshaya", "SriRam", "Srisaiprasath", "Srivatsan");
var-dump ($children);
?>

(i) String is a collection of characters within the double or single quotes like "Computer Application" or Computer Application
(ii) Space is also considered as a character.
Example:
< ?php
\(\$\)x = "Computer Application";
\(\$\)y = 'Computer Application';
echo \(\$\)x;
echo " <br">;
echo \(\$\)y;
?>

(i) PHP script can be written inside of HTML code and save the file with the extension of .php.
(ii) Embedded PHP file get executed in the webserver, the browser receives only the HTML and other client side Iiles.

(i) HTML script embed Tags looks like HTML script tags.
(ii) Syntax is
<script language= "php">
echo "This is HTML script tags";
</script>
(iii) File is saved with extension of .php.
(iv) This .php file is ready to execute from webserver and. generate response to client machine.

(i) Web development concept describes about website development and hosting through network
(ii) It also includes web content generation, web page designing, website security and so on.

WebServer software that runs on server hardware, governs the server side scripting compilation into an intermediate byte-code that is then interpreted by the runtime engine.

(i) This architecture is used for the server, and accessed by client through more than one layer interaction.
(ii) The programmer could decide the count of business logic layers according to the software requirement. For this reason this model is also known as multi/ three tier Architecture.

(i) Single Tier Architecture is used for server accessed by client.
(ii) Client application runs inside the server machine itself
(iii) It acts as a single layer interaction.

In the evolution of network architecture,
(i) Various critical network related problems are getting resolved by client server architecture model.
(ii) Client server architecture introduces applications sharing mechanism between two different hardware system over the network Internet/ Intranet.

Internet and WWW concepts required a new set of programming languages over the network communication. These programming languages are recently called as web scripting languages.

Internet and web based applications are performing an important role in business and entertainment industry.

(i) Resource is a specific variable.
(ii) It hasa reference to an external resource .
(iii) These variables hold specific handlers to handle files and database connections irrespective PHP program.

(i) The var_dump( ) function is used to dump information about a variable.
(ii) This function displays structured information such as type and value of the given variable.
(iii) Arrays and objects are explored recursively with values indented to show structure.
Example:
\($\)x = "COMPUTER APPUCATION!";
\($\)x = null;
var dump(\($\)x);
?>
OUTPUT: NULL

(i) Open Source
(ii) Case Sensitive
(iii) Simplicity Program language
(iv) Efficiency Program language
(v) Platform Independent Program language
(vi) Security Program language
(vii) Flexibility Program language
(viii) Real-Time Access Monitoring Program language