Module 3.1: Scripting and the Role of Scripting Languages

Midterm topic

Scripting Languages

• All scripting languages are programming languages. The scripting language is basically a language where instructions are written for a run time environment.

• They do not require the compilation step and are rather interpreted.

• It brings new functions to applications and glue complex system together.

• It is designed for integrating and communicating with other programming languages

bash

• It is a scripting language to work in the Linux interface.

• It is a lot easier to use this than to create scripts than other programming languages. It describes the tools to use and code in the command line and create useful reusable scripts and conserve documentation for other people to work with

Node.js

• It is a framework to write network applications using JavaScript.

• Corporate users of this include IBM, LinkedIn, Microsoft, Netflix, Paypal, Yahoo for real-time web applications.

Ruby

• It is known for its flexibility and has allowed developers to create innovative software. It is a scripting language great for web development

Python

• It is easy, free and open source. It supports procedure-oriented programming and object-oriented programming

• Is an interpreted language with dynamic semantics and huge lines of code are scripted and is currently the most hyped language among developers

Perl

• A scripting language with innovative features to make it different and popular. Found on all windows and Linux servers.

• It helps in text manipulation task. High traffic websites that use this include priceline.com, IMDB

• Old UNIX language

• Excellent web scripting language

Active Server Pages (ASP)

• Server side scripting language

• Developed by Microsoft

• Good at connecting to Microsoft databases

• Runs only on Microsoft servers

PHP (Hypertext Pre-Processor)

• Especially good at connecting to MySQL

• Very popular language

• Runs on UNIX and Windows

• HTML-embedded scripting language

• Syntax looks like C, JAVA, and Perl

• Generate dynamic content and good user interface

• Server side execution

JSP (Java Server Pages)

• Developed by Sun

• Uses Java

• Provide server-specific framework like Microsoft’s ASP

CGI (Common Gateway Interface)

• Servers-side solution

• Needs to launch separate instance of application for each web request

• Allows direct interaction with users

ASP.NET

• Server-side technology to create faster, reliable, and dynamic web pages

• Supports .NET framework languages (C#, VB.NET, JScript.NET)

• Provides flexibility to designers and developers to work separately

VBScript

• Microsoft’s scripting language

• Client side scripting language

• Very easy to learn

• Includes the functionality of Visual Basic

JavaScript

• Client-side Scripting language

• Easy to use programming language

• Enhance dynamics and interactive features of a web page

• Allows to perform calculation, write interactive games, add special effects, customize graphic selections, create security passwords

Applications of Scripting Languages

• Scripting languages are used in web apps. It is used in server side as well as client side.

• Scripting languages are used in system administration. For example: Shell, Perl, Python scripts

• It is used in Games application and Multimedia

• It is used to create plugins and extensions for existing applications

(1) Programming Languages

• Provides human-readable instructions that direct computer hardware to perform specific tasks. Because computers only process binary code made of 0s and 1s, compilers translate these high-level instructions into machine-level language by scanning the entire codebase at once to catch errors before execution.

• Languages like C, C++, C#, and Java use this process to build software applications and hardware drivers.

(2) Scripting Languages

• Are a subcategory of programming languages designed to control, automate, and connect other software rather than operate independently.

• Instead of using a compiler to scan code all at once, scripting languages rely on an interpreter to process instructions line by line at runtime.

• Primarily used in web development, popular examples include JavaScript, PHP, Python, Perl, and VBScript.

(3) Markup Languages

• They differ from programming and scripting languages because they control data presentation, structure, and design without using logic or algorithms.

• Instead of executing calculations or conditional processing, languages like HTML, CSS, and XML instruct web browsers on how to format and style page elements like layouts, headings, and tables.

• Primarily used for web design, markup languages focus strictly on shaping how information is structured and visually presented.

Server-side Scripting Language

(Types of Scripting Language)

• Can use huge resources of the server

• Complete all processing in the server and send plain pages to the client

• Reduces client-side computation overhead

Client-side Scripting Language

(Types of Scripting Language)

• Does not involve server processing

• Complete application is downloaded to the client browser

• Client browser executes in locally

• Are normally used to add functionality to webpages e.g different menu styles, graphic displays or dynamic advertisements

Creating and Executing Scripts

• A JavaScript file is, like HTML and CSS files, a simple text file. It doesn’t have a header or any other special sections. It doesn’t even have tags. Its just pure js code. The entire contents of a js script file that holds the two functions in the example below would be:

1 function sayHi() {
2 alert("Hello world!");
3 }
4 function sayBye() {
5 alert("Buh-bye!");
6 } 

TRUE

• You include a JavaScript file in an HTML file the same way you include an external CSS file—with an opening and closing tag.

<script src="whatever.js"></script>

TRUE

• For the same reason that it's a good idea to put JavaScript code at the end of the body section, it's a good idea to place the markup that includes JavaScript files at the end of the body section.