Following are the steps to create a simple AD rotator script without using database in PHP:

- All the ad’s can be collected in one place and be displayed randomly.rand() function can be used for this purpose.

- In order to NOT use any database, a flat file can be used to store the ad’s.

- In order to store the Ad’s information (HTML code), a flat file say “ad.txt” can be created.

- The random number can be stored in a variable 

$result_random=rand(1, 100);

- Conditions can be checked to display the ad’s.

if($result_random<=70)

{

      echo "Display ad1";

}

By the use of void set_time_limit(int seconds)

Set the number of seconds a script is allowed to run. If this is reached, the script returns a fatal error. The default limit is 30 seconds or, if it exists, the max_execution_time value defined in the php.ini. If seconds is set to zero, no time limit is imposed.

When called, set_time_limit() restarts the timeout counter from zero. In other words, if the timeout is the default 30 seconds, and 25 seconds into script execution a call such as set_time_limit(20) is made, the script will run for a total of 45 seconds before timing out.

The difference lies with the execution of the languages. PHP is server side scripting language, which means that it can’t interact directly with the user. Whereas, JavaScript is client side scripting language, that is used to interact directly with the user.

- The principle of least privilege is used to provide more security to the computer programs. 

- The principle allows the designing of the program such that any unauthorized access is not allowed and only the person who owns the program will be able to access it. 

- The services provided should be able to access only those products that need the services. 

- Web servers that are involved in responding the queries of the web users provide only accessing to the HTML files that will serve the purpose of the programs. 

- Computer programs should be made such that it provides secure features of logging into the program with proper authentication.

The web hosting on the server can be accomplished by using the IP based hosting that provides resources and services as follows:

- IP based hosting provides dedicated IPs that consists of virtual hosts and having the different IP address. 

- Web server is configured with different and multiple physical network interfaces using the same physical interface. 

- Web server uses this IP address to connect the client with the server to determine the web site that provides the client a view of it. 

- IP addresses provide the resources that are required in order to use the SSL certificates and other resources rather than shared certificate.

The XML DOM (document object model) is used the access and management of xml. It is a platform that is language neutral and allows a program or a script to dynamically access a document. It also allows the updation of content as well as the structure and style of the document. It is responsible for the defining of the object and properties of all xml elements as well as to define the methods for their access. There are various methods that can be used in xml dom such as:

- getElementsByTagName: used to call a specific user defined tag.

- setAttribute: used to change the value of an existing attribute.

- appendChild: used to add a child node to another node.

Asc() - Returns ANSI Character Code 

Chr() - Returns Character from ANSI Code 

InStr() - Find a string within another 

InStrRev() - Find a string within another (Reverse) 

LCase() - Convert a string to lowercase 

Left() - Crops a string from left 

Len() - Determine the length of a string 

LTrim() - Remove leading spaces from a string 

Mid() - Crops a string 

Replace() - Replace a substring within a string 

Right() - Crops a string from right 

RTrim() - Remove trailing spaces from a string 

Space() - Creates a string with the specified number of spaces 

StrComp() - Compare two strings 

String() - Creates a repeated character string 

StrReverse() - Reverse the characters of a string 

Trim() - Remove both leading and trailing spaces from a string 

UCase() - Convert a string to uppercase 

This is a scripting language developed by Microsoft and is based loosely on Visual Basic. Its functionality in a web environment is dependant upon either an ASP engine or the Windows Scripting Host, and must be used on a Windows hosting platform.