Tuesday 30 April 2013

Scriptive Language

 

How a scripting language can improve functionality



Scripting languages, which can be embedded within HTML, commonly are used to add functionality to a Web page, such as different menu styles or graphic displays. These types of languages are client-side scripting languages, affecting the data that the end user sees in a.
 

Validation


Client side

In Client side the scripting does all the calculations on the user's computer. The web browser or a specific plug-in reads the script and converts it into a visual web page.

Front end context uses scripting through a user interface. There are many ways a user interface uses scripting
one is that it re sizes parts of the web page to make it all fit properly. It also re sizes boxes.
Most of the information that the user enters into the website stays in the client side and sometimes sent back to the server. JavaScript can obtain external files and images. It then exploits all of this using web analytic programs, the server can retrieve all the information from all of these.


Server side
Server-side scripting is a web server technology in which a user's request is verified by running a script directly on the web server to generate dynamic web pages. It is usually used to provide interactive web sites that interface to databases or other data stores

Form validation used to occur at the server after the client had entered all necessary data and then pressed the Submit button. If some of the data that had been entered by the client had been in the wrong form or was simply missing, the server would have to send all the data back to the client and request that the form be resubmitted with correct information. This was really a lengthy process and over using servers. JavaScript provides a way to validate form's data on the client's computer before sending it to the web server. Form validation generally performs two functions.
  • Basic Validation - First of all the form must be checked to make sure data was entered into each form field that required it. This would need just loop through each field in the form and check for data.
  • Data Format Validation - Secondly the data that is entered must be checked for correct form and value. This would need to put more logic to test correctness of data


By doing the validation checks on the client side, it saves a lot of processing and server usage which helps keeps the system goin for longer. showing you how to check for the following:
  •  If a text input is empty or not
  •  If a text input is all numbers
  • If a text input is all letters
  • If a text input is all alphanumeric characters (numbers & letters)
  • If a text input has the correct number of characters in it (useful when restricting the length of a username and/or password)
  •    If a selection has been made from an HTML select input (the drop down selector)
  •    If an email address is valid



GUI


A program interface that takes advantage of the computer's graphics to make the program easier to use. Well-designed graphical user interfaces can free the user from learning complex command languages. On the other hand, many users find that they work more effectively with a command-driven interface, especially if they already know the command language. They use windows, icons and menus to carry out commands such as opening files, deleting files and moving files. They are often used in computers, mobile devices and protable games.

JavaScript


JavaScript is a programming language used to make web pages interactive. It runs on your visitor's computer and doesn't require constant downloads from your website. JavaScript is often used to create polls and quizzes. Javascript can interact with HTML source code, enabling Web authors to spice up their sites with dynamic content.
JavaScript is used in Web site development to do such things as:

  • Automatically change a formatted date on a Web page
  • Cause a linked-to page to appear in a popup window
  • Cause text or a graphic image to change during a mouse rollover
JavaScript uses some of the same ideas found in Java, the compiled object-oriented programming derived from C++. JavaScript code can be imbedded in HTML pages and interpreted by the Web browser (or client). JavaScript can also be run at the server as in Microsoft's Active Server Pages before the page is sent to the requestor. Both Microsoft and Netscape browsers support JavaScript, but sometimes in slightly different ways.

Jquery


The purpose of jQuery is to make it much easier to use JavaScript on your website. jQuery takes a lot of common tasks that require many lines of JavaScript code to accomplish, and wraps them into methods that you can call with a single line of code. jQuery also simplifies a lot of the complicated things from JavaScript, like AJAX calls and DOM manipulation. The jQuery library contains the following features:

·      HTML/DOM manipulation
·      CSS manipulation
·      HTML event methods
·      Effects and animations
·      AJA
·      Utilities


References

Btec book 2, date accessed: 01/05/2013
Ws, date accessed: 01/05/2013- http://www.w3.org/TR/html4/interact/scripts.html
Ontopia, date accessed: 01/05/2013- http://www.ontopia.net/i18n/index.jsp 
W3schools, date accessed: 08/05/2013 - http://www.w3schools.com/jquery/jquery_intro.asp