Free Online Programming Tutorials

Introduction to DHTML

YourOnlineTutor — Tue, 09 Mar 2010 21:57:22 +0000

DHTML is an entirely “client-side” technology

- It does not require plugins and embeds seamlessly into a web page.

- Underlying technologies-HTML, CSS, javaScript

- Allows changing of content, color, fonts, etc. dynamically

What is DHTML?

It is considered to be made up of HTML, Cascading Style Sheets (CSS), and Scripting language.

All three of these components are linked via Document Object Model (DOM).

DOM

For those who don’t know about DOM, it is the interface that allows scripting languages to access the content, style, and structure of the web documents and change them dynamically

What is RDF?

Wed, 03 Feb 2010 06:17:59 +0000

The resource description framework (RDF), is an XML-based application being developed in the W3C…

It brings together ideas from the meta content format, or MCF (technology acquired by Netscape from Apple Computer Inc.) and XML-Data (defined in a proposal recently submitted to the W3C by Microsoft, ArborText, DataChannel, and Inso).

RDF allows for generalized searching of information without application-specific rules, such as those defined in DTDs. RDF allows a complementary view of data through graphs and nodes, rather than through a structured tree, which the current XML technology enables. RDF, together with XML schemas, will provide a standard way for developers to write these relationships down for broad classes of XML elements.

The crucial technologies that will deliver value this year and next are XML for structured data, XML namespaces to make names unique and recognizable, and new XML tags that add meaning to data so smarter search engines can perform better searches.

Insight to Cookies: Advanced Programming Concepts

Fri, 06 Nov 2009 20:07:31 +0000

Here’s more info on cookies that you may want to know -

• When the cookie is requested for the first time, the cookie is stored using the set-Cookie entry in the header of the response from the server.
• Set-cookie : name= value; expires = Date;Path=PATH;domain=DOMAIN;secure

Optional attributes are –

• Expires =Date
• Path=PATH ( path of the URL for which the cookie is valid)
• Domain – Domain specifies the domain for which the cookie is valid.
• Secure specifies that the cookie has to be transmitted only over a secure link.
• Exampleofcookies

What is JavaScript: Introduction to JavaScript

Thu, 05 Nov 2009 20:01:44 +0000

Wondering what is JavaScript? Well, here’s a brief introduction to JavaScript, along with some of its common uses…

• Javascript is integrated with HTML and Navigator2.02.
• Javascript facilitates the developer with the properties related to document windows ,frames,forms,loaded documents and links.
• This is an interpreter based language and the source code files are directly executed at runtime.
• Javascript includes built-in objects related to the current windows and the documents and as well as objects such as Math,String functions and Date Functions.
• It is object oriented language and supports instances ,methods, properties.

Integrating JavaScript with HTML

Mon, 05 Oct 2009 20:01:53 +0000

To integrate javascript with the html, the following syntax must be used.

< script language=“JavaScript” >
–Javascript program–
< /script >
The javascript can be included anywhere in the header or body of an html.

To hide the javascript from other browsers the following is used.
< ! -- hide the script from other broswsers
// stop hiding from other browsers - - >

HelloWorld Filter: Understanding Filters in Java Servlets

Thu, 17 Sep 2009 19:56:40 +0000

package examples.filters;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

/**
* @version 1.0
* @author
*/

public class HelloWorldFilter implements Filter

{
/**
* @see javax.servlet.Filter#void ()
*/
public void destroy() {

}

/**
* @see javax.servlet.Filter #void (javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
*/

public void doFilter(
ServletRequest req,
ServletResponse resp,
FilterChain chain)
throws ServletException, IOException {
System.out.println(”Entering Filter”);
req.setAttribute(”hello”,”HelloWorld”);
chain.doFilter(req, resp);
System.out.println(”Exiting Filter”);

}

/**
* Method init.
* @param config
* @throws javax.servlet.ServletException
*/
public void init(FilterConfig config) throws ServletException {

}

Frames Framesets and No-Frames in HTML

Tue, 08 Sep 2009 19:37:35 +0000

This is a container which hosts the FRAME,
FRAMESET, and NOFRAME tags.

< FRAMESET
COLS=col-widths
FRAMEBORDER=yes-no
FRAMESPACING=spacing
ROWS=row-heights
BORDERCOLOR=“colorname/rgb format” >

Frames

Defines a single frame in a frameset and there is no matching end tag as this is not a container.

< FRAME
ALIGN=align-type
FRAMEBORDER=yes-no
MARGINHEIGHT=height
MARGINWIDTH=width
NAME=name
SCROLLING=yes-no
SRC=address >

Here’s a simple example

< FRAMESET cols="83,*" >
< FRAME SRC="directory.html" SCROLLING=NO MARGINWIDTH=1 MARGINHEIGHT=1 >
< FRAMESET rows="20%,80%" >
< FRAME SRC="banner.html" >
< FRAME SRC="home.html" NAME="MAIN-WINDOW" >
< /FRAMESET >
< /FRAMESET >

NOFRAMES

Content viewable by browsers that do not support frames. Browsers that support frames will ignore all content between the beginning and ending NOFRAMES tags.

Here’s a quick example to get a better understanding -

< FRAMESET >
< NOFRAMES >You need Internet Explorer 6.0 or higher to view frames!< /NOFRAMES >
< /FRAMESET >

Using Area and Map Tags in HTML

Mon, 07 Sep 2009 19:34:41 +0000

Area Specifies the shape of a hyperlink “hot spot” in a client-side image map.

< AREA
ALT=text
COORDS=coordinates
HREF=url
SHAPE=CIRC | CIRCLE | POLY | POLYGON | RECT | RECTANGLE >

On the other hand, < MAP NAME = name > Specifies a collection of hot spots for a client-side image map.

NAME=name — Gives the MAP a name so it can be referred to later.

Let us consider a simple example -

< MAP NAME=" map1 " >
< AREA ... >
< AREA ... >
< /MAP >

What is Cookie: Advanced Programming Concepts

Sat, 05 Sep 2009 20:05:05 +0000

Cookie is a method of storing information about the page returned by the server and stored locally in the browser.

Purpose of the cookie is to store the state of the client enabling the server to know about the client’s previous actions on the page downloaded…

When the user requests for a page to the server via http protocol , the server sends the http response to the client along with header information.

The header contains the information about the document being returned.

Format– Field-name :information

Golden rules of User Interface Design

Tue, 25 Aug 2009 09:01:59 +0000

Here are some of the golden rules of UI Design -

• Strive for consistency
• Enable frequent users to use shortcut
• Offer informative feedback

• Design dialog to yield closure
• Offer error prevention and simple error handling
• Permit easy reversal of actions
• Reduce short term memory load