Client side languages (Javascript and Jquery)

Javascript language was initially (during web1.0 era) used for client side validations only. But in current scenario, its purpose has changed drastically. It is widely used for user interactivity, friendliness, validations, high performance and speed, responsiveness (for handheld devices like mobile, tablet etc.) and many more purposes.

Due to all these reasons, client side languages like JS and Jquery are used. As websites are mostly browser/ device dependent, so JS is heavily used. This can impact loading time and performance of the website. To overcome this, many JS frameworks and libraries are launched in the market.  All these have their own pros and cons.

Difference between Framework and library.

A library is essentially a set of functions that you can call, these days usually organized into classes. Each call does some work and returns control to the client.

A framework embodies some abstract design, with more behavior built in. In order to use it you need to insert your behavior into various places in the framework either by subclassing or by plugging in your own classes. The framework's code then calls your code at these points.

Refer http://en.wikipedia.org/wiki/List_of_JavaScript_libraries  to get the list of most commonly used Javascript frameworks and libraries.

Cascading Stylesheets (CSS)

CSS3 is latest standard these days. It supports all previous features of css2 as well. Important  modules added in css3 are:

• Selectors
• Box Model
• Backgrounds and Borders
• Image Values and Replaced Content
• Text Effects
• 2D/3D Transformations
• Animations
• Multiple Column Layout
• User Interface

All these modules cover all latest features of css like gradient, shadow, effects, opacity etc.

Basics  and advanced details of CSS3 can be covered from w3c website http://www.w3schools.com/css/css3_intro.asp w3c validator validate the css

CSS frameworks are in demand these. These frameworks are based on some backend environment. Dynamic stylesheet language, extends the CSS with dynamic behavior such as variables, mixins, operations and functions.

Benefits of using frameworks are:

•  File size minimized.
• Code reusability increases.
• Encourage grid based design.
• No need to reinvent the wheel.
• Enables cross browser functionality.
• Speeds up development.

Most commonly used css frameworks are:

1. LESS Framework:  Refer http://lesscss.org/ and http://lessframework.com/    

It runs on both server side (using Node.js) and client side (in modern browsers only).

Less.js need to add on page to run less stylesheet.

File extension is .less

2. SASS Framework: Refer http://sass-lang.com

Ruby-on-rails required in backend to run SASS file.

File extension is .sass or .scss

Info on XHTML

XHTML (Extensible Hyper Text Markup Language): Its extended, cleaner and sticker version of HTML, almost identical to HTML4.0. It is based on XML application, so one can say its a combination of HTML and XML.

Basic difference between HTML and XHTML are:

• XHTML elements must be properly nested.
• XHTML elements must always be closed.
• XHTML elements must be in lower case.
• XHTML documents must have one root element.

XHTML syntax rules are:

• Attribute names must be in lower case.
• Attribute values must be quoted.
• Attribute minimization is forbidden.
• The id attribute replaces the name attribute.
• The XHTML DTD defines mandatory elements :Doctype declaration, html,head and body tags are mandatory in XHTML documents.

Doctype specifies which DTD(Document type definition) is used by XHTML document. A DTD specifies the syntax of a web page in SGML. An XHTML DTD describes in precise, computer-readable language, the allowed syntax of XHTML markup.
There are 3 types of XHTML DTD

1. XHTML 1.1 Strict :for clean markup and free of presentational clutter. It declared as: !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"
2. XHTML 1.1 Transitional : It is used when user want to use HTML presentational features. It declared as: !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"
3. XHTML 1.1 Frameset : When HTML frames are used. It declared as: !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd"

After creating xhtml file and adding correct DTD, it can be validated using W3C Validator, using link http://www.w3schools.com/xhtml/default.asp