M2: Discuss how a scripting language can improve functionality

A scripting language is a tool, which is used to add functionality to other software. It is not as powerful as a full programming language and it is generally designed for simple tasks like creating interactive menus or searching databases. HTML can help by creating static webpages but it can’t do everything and that’s why JavaScript and PHP can make the websites dynamic with user interaction. JavaScript is very important to help make a website functional. Scripting languages that can be embedded within HTML are commonly used to add functionality to a webpage such as different menu styles or graphic displays or to server dynamic advertisements. These types of languages, which can enable functionality to work, are client side scripting languages, which affect the data that the end user sees in a browser.

If a website used JavaScript effectively, then it can add user prompts, navigation assistance, user choice confirmation and many other client side calculations. JavaScript is used to improve the content and functionality of websites. Businesses such as Amazon use JavaScript to improve their website by alerting users and opening popups. By using a scripting language it will make a more interactive website because the page will respond to the users actions instantly. From the developer side, it allows more control over the appearance and actions of the webpage

However, there are some browsers that are out-dated and some people will still use them and they may not run scripting languages, this could result in the webpage not running properly. From a developer side t takes a lot of time to add scripts to a webpage in terms of both writing the scripts and testing them. Some browsers which can be used are: Mozilla Firefox, Google Chrome, Apple Safari & Internet Explorer.

There are many reasons to use a scripting language in a webpage. The main reasons to use a scripting language are shown below:

 There are often times when we wish to automate a simple task – a scripting language helps by running several programs in a row, installing programs, even writing a simple script or GUI to run a program that needs many parameters

Scripting languages allow us to write code quickly and run it without any compilations. They also have good support for launching processes and controlling them, etc.

By using a script, you would never be confused and think ‘where is the source’ because the script is the source

Every website has cookies. A cookie is a small piece of information which is sent from a website that is stored on the visitors computer. It is a message given by the browser to a web server.The browser will store the message in a text file and then the message will be sent back to the server each time the browser requests a page from the server. A cookie is mainly used to identify the user, there are different types of cookie which are shown below:

• Session cookie – this is a cookie that is only stored temporarily while the user browses the site, this is created when a expiry date or time is not given

• Persistent cookie – this is a cookie which lasts longer than the users that visit on the site

• Name cookies – this is a cookie that stores the login information in a cookie so next time the visitor loads the site, their information will be stored. The site could also display something like a welcome message which is personalised for the user such as Amazon say ‘ Hello, ……..’

When using JavaScript you can add rollover buttons. A rollover button is a web button that changes its appearance when the mouse moves over it. It contains three states, which are normal, over and down. Normal state applies to when the mouse is off the button, over state applies to when your mouse rolls over the button and down state applies to when you click on the button. Rollover buttons are different to static web buttons because they are dynamic in nature and allow you to change the colour or style of the button with the movement of the mouse.

Client side validation is optional but it has a lot of benefits, which include faster response to the user than server side validation, a reduction in web server loads, and a reduction in network traffic. Client side validation can be implemented as interactive validation. Validation in the client tier is unreliable because the user can bypass the validation through design, error or configuration. Client side validation is a tool that should be used only to improve speed, reduce load and add effects.

Validation is very important to web database application. Validation makes sure that data meets user and system requirements. Client tier validation happens at the client browser before a request is sent to the server and is usually validation of <form> data. The most common way to user client tier validation is suing the scripting language best known as JavaScript.

Server side validation is usually performed in middle tier script and is the most important validation tool. When data is inserted, updated or deleted at the database. Trapping errors using the PHP error function is hard because it has a unnecessary network and DBMS overhead, and I is hard to present to the user is a useful way. It is better to use PHP scripts to validate data and make sure all constraints of the database are bet before modifying the database.

As mentioned above, there are two main types of scripting languages for the web. The two scripting languages are client side and server side. These two scripting languages are explained below:

Client-side: The client is the system on which the web browser is running. JavaScript is the main client-side scripting language for the Web. The browser interprets client-side scripts. Client side scripting has a process, which is shown below:

The user requests a web page from the server

The server finds the page and sends it to the user

The page is displayed on the browser with any scripts running during or after display

Client side scripting is used to make web pages change after they arrive at the browser. It is useful for making web pages a bit more interesting and user friendly. It can provide useful gadgets such as calculators, clocks, etc.

Client side scripts rely on the users computer. If that computer is slow then it may run slowly. They may not run at all if the browser does not understand the scripting language, this is one reason why it is important to have recent browsers because they have to run on the users system and the code, which makes up the script is there is the HTML for the user to look at. An example of client side scripting is JavaScript & VB

Server Side: the server is where the web page and other content stays. The server sends pages to the user/client when requested. The process for this is shown below:

The user requests a web page from the server

The script in the page is interpreted by the server creating or changing the page content to suit the user

The page in its final form is sent to the user and hen cannot be changed using server side scripting

The use of HTML forms or clever links allow the data to be sent to the server and processed. The results may come back as a second web page. Server side scripting is often used for allowing users to have individual accounts and providing data from databases. It allows a level of privacy, personalisation and provision of information that is very powerful. E-commerce and social networking sites all rely on server side scripting to keep information safe.

The script is interpreted by the server, which means that it will always work the same way. The user never sees server side scripts, which is useful so they can’t, copy their code. They run on the server and generate results, which are sent to the user. Running all these scripts puts a lot of loads onto the server but nothing on the user’s system. The server side system has to be powerful so it can deal with the entire load.  An example of sever side scripting is PHP, Python, Ruby, etc.

The difference between client side and server side:

The difference between the two scripting languages are simple, the client side code is processed by the client/browser while the server processes the server code. A typical web page for the client is made of some HTML which is implemented by CSS or JavaScript. The browser never sees server side code and the browser should never need to be aware of server side scripts such as PHP. Server side code is browser independent, which means that if the page you create looks different in Internet Explorer, and then it does the same in Opera

Advantages and Disadvantages of client side scripting

Advantages	Disadvantages
Allow more interactive by immediately responding to users actions	Not all browsers support scripts and because of this errors can happen
Execute quickly because they don’t need a trip to the server	Different browser and browser versions support scripts differently
May improve the usability of websites for users	More development time and effort may be required
Can give developers more control over the look and behaviour of widgets	Developers have more control over the look and behaviour of widgets
Can be substituted with alternatives such as HTML
Are reusable and obtainable from many free resources

Advantages and Disadvantages of server side scripting

Advantages	Disadvantages
It reduces the load on the users computers because it don’t need plugins	It requires the scripting software to be installed on the server
You can use it to dynamically create pages	Many scripts require databases in order to store dynamic data
Website owners can create their own applications without editing code	The nature of scripts create new security concerns

Advantages and Disadvantages of JavaScript

Advantages	Disadvantages
Allows websites to interact with the client	Browser must support the language such as JavaScript
Browser detection to inform the user that the page they are trying to view only works on a certain browser	Some languages are written with only one browser such as VB script for Internet explorer
Can be used to redirect and alert the user	JavaScript can be used maliciously because it executes code
Used to store cookie information which can be used to keep users logged in	Different users can produce different results
Most browsers support main scripting languages

Bibliography

http://uk.answers.yahoo.com/question/index?qid=20130219055037AAaP9Xp

http://www.webopedia.com/TERM/C/cookie.html

http://www.w3schools.com/js/

http://www.enable-javascript.com

http://www.ehow.com/about_6169025_rollover-button_.html

http://unit20-ict.blogspot.co.uk/2013/01/m2.html
 

http://en.wikipedia.org/wiki/Client-side_scripting

http://www.webopedia.com/TERM/C/client_side.html

http://wiki.answers.com/Q/What_are_client_side_and_server_side_scripting

http://www.pcmag.com/article2/0,2817,1554984,00.asp

http://thescriptinglanguages.wikispaces.com/How+scripting+languages+and+javascript+improve+functionality+M2

 http://www.serverschool.com/server-software/advantages-of-server-side-scripting/