Q.1 what is web browser?
A.1 A web browser or Internet browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web.
When you sit down and look at web pages, you are using a web browser. This is the piece of software that communicates with web servers for you via the HTTP protocol, translates HTML pages and image data into a nicely formatted on-screen display.
The most common web browser, is Microsoft Internet Explorer, Firefox browser and its relatives, including Netscape, Safari , Opera, Lynx browser.
Q.2 DNS ( domain name system)?
query to a name server to resolve a domain.
The DNS protocol utilises Port 53 for its service. This means that a DNS server listens on Port 53 and expects any client wishing to use the service to use the same port.
addresses ( or vice versa)
which is a fancy way of saying that its layers are arran ed in a
definite order and that its data is distributed across a wide range of machines (just like the roots of a tree branch out from the main root).
Top-level domains :
Domain Used By
========== ==========
.com Commercial organizations, as in novell.com
.edu Educational organizations, as in ucla.edu
.gov Governmental agencies, as in whitehouse.gov
.mil Military organizations, as in army.mil
.org Nonprofit organizations, as in redcross.org
.net Networking entities, as in nsf.net
.int International organizations, as in nato.int
Q. what is HTML?
A. HYPER TEXT MARK UP LANGUAGE
The language used to develop web pages is called HYPER TEXT MARK UP LANGUAGE(html). HTML is the language interpreted by a web browser. Web pages are called HTML documents. HTML is a set of special codes that can be embedded directly into the text to add formatting and linking information. HTML is specified as tags in an HTML document.
HTML TAGS
Tags are the instructions that are embedded directly into the text of the document. An HTML tag is a signal to a browser that it should do something other than just throw text up on the screen. By convention all HTML tags begin with an open angel bracket (<) and end with an close angel bracket (>).
HTML tags can be of two types:
PAIRED TAGS: A tag is said to be a paired tag if comes with a companion tag, flanks the text. For example <B> tag is a paired tag with its companion tag </B> causes the text contained between them to be rendered in bold. In paired tag the first tag (<B>) is often called the opening tag and the second tag (</B>) is called the closing tag.
The opening tag activates the effect on and the closing tag turns the effect off.
SINGULAR TAGS: The second type of the tag is the singular tag or stand-alone tag. A stand-alone tag does not have a companion tag. For example <BR> tag will insert a line break. This tag does not require any companion tag.
THE STRUCTURE OF HTML PROGRAM
Every HTML program has a rigid structure. The entire web page is enclosed with <HTML> </HTML> tags. Within these tags two distinct sections are created using the <HEAD> </HEAD> tag and the <BODY> </BODY> tags. These sections are described below.
DOCUMENT HEAD:
Information placed in this section is essential to the inner working of the document and has nothing to do with the content of the document. With the exception of the information contained witHin the <TITLE> </TITLE> tags, all the information placed within the <HEAD> </HEAD> tags is not displayed in the browser. It is indicated in the title bar.
<HEAD>
<TITLE>……………… </TITLE>
</HEAD>
DOCUMENT BODY:
The tag used to indicate the start and end of the main body of the textual information are:
<body>
----------
-----------
-------------
</body>
Page defaults like background color, text color can be specified as attribute of the body tag. The attributes that the <BODY> tag takes are:
BGCOLOR: Changes the default background color to whatever color is specified with this tag. The user can specify the a color by name.
BACKGROUND: specifies the name of the gif file that will be used as the background of the document.
TEXT: changes the body text color from its default value to the color specified with this attribute.
Example:
<BODY BACKGROUND=”STARFIED.GIF” TEXT=RED>
NOTE: ALL THE CODE IS WRITTEN INTO A NOTE PAD AND TO SAVE IT WE USE THE FILE EXTENSION .HTML. FOR EXAMPLE: SUKHI.HTML.
LINE BREAKS:
When text needs to start from a new line and not continue on the same line(without skipping a blank line), the <BR> tag is used. This tag simply jumps to the start of the next line.
For example:
Hello<BR> hoe are u<BR> welcome to my site.
Output:
Hello
How are u
Welcome to my site.
EMPHASIZING MATERIAL IN A WEB PAGE
Document pages are usually divided into sections and sub sections , which needs to be emphasized. HTML provides certain heading styles and horizontal rules, which helps break text into logical sections with visual appeal.
Heading Styles: HTML supports six different levels of heading. The highest – level header format is <H1>. And the lowest level is <H6>. All the styles appear in boldface and the size of the heading depends on the level chosen.
For example:
<h3> The early years</h3>
Output:
The early years
Drawing lines: The <HR> tag draws lines and horizontal rules. This tag draws a horizontal line across the whole page, wherever specified. The attributes to the <HR> tag are:
ALIGN: aligns the line on the screen, which is by default aligned to the center of the screen. It has three different values left, right and center.
SIZE: changes the size of the rule.
WIDTH: sets the width of the rule. We can set any no. 1,2,3,-----.
TEXT STYLES:
BOLD: displays the text in bold face.
<B>----------</B>
ITALICS: displays the text in italics.
<I>-----------</I>
UNDERLINED: displays text as underlined.
<U>-----------</U>
CONTROLLING FONT SIZE AND COLOR:
All the text specified within the tags <FONT> and </FONT> will appear in the font, size and color as specified as attributes of the tag <FONT>. The attributes are:
FACE: sets the font to the specified font name.
SIZE: sets the size of the text in numbers by default it is 3.
Color: sets the color of the text.
For example:
<FONT FACE=”TIMES NEW ROMAN” SIZE=6 COLOR=RED>-----------------------------</FONT>
LIST
TYPES OF LISTS
UNORDERED LIST(BULLETS)
An unordered list start with the tag <UL> and ends with </UL>. Each list item starts with the tag <LI>. The attributes that can be specified with <li> are
Type: specifies the type of the bullet.
Type= fillround will give a solid round black bullet.
Type=square will give a solid square black bullet.
For example:
Some of these products include:
<UL TYPE=FILLROUND>
<LI>FLOPPIES
<LI>HARD DISK
<LI>MONITER
</UL>
OUTPUT:
Some of these products include:
FLOPPIES
HARD DISK
MONITER
ORDERED LIST:
An ordered list start with the tag <OL> and ends with </OL>. Each list item starts with the tag <LI>. The attributes that can be specified with <li> are:
Type: controls the numbering scheme to be used.(1, A, a, I,i)
Start: alters the numbering sequence. Can be set to any numeric value.
Value: changes the numbering sequence in the middle of the ordered list. It is to be specified with the <LI> tag.
For example:
Some of these products include:
<OL TYPE=”1” START=3>
<LI>FLOPPIES
<LI VALUE=7>HARD DISK
<LI>MONITER
</OL>
OUTPUT:
Some of these products include:
FLOPPIES
7. HARD DISK
8. MONITER
DEFINITION LIST:
Definition list values appear with in tags <DL> & </DL>.definition lists consist of two parts.
Definition term: appears after the <DT>.
Definition description: appears after the <DD>
FOR EXAMPLE:
<DL>
<DT> KEYBOARD
<DD> AN INPUT DEVICE
<DT> PRINTER
<DD> AN OUTPUT DEVICE
</DL>
OUTPUT:
KEYBOARD
AN INPUT DEVICE
PRINTER
AN OUTPUT DEVICE
A.1 A web browser or Internet browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web.
When you sit down and look at web pages, you are using a web browser. This is the piece of software that communicates with web servers for you via the HTTP protocol, translates HTML pages and image data into a nicely formatted on-screen display.
The most common web browser, is Microsoft Internet Explorer, Firefox browser and its relatives, including Netscape, Safari , Opera, Lynx browser.
-
Many browsers have a “history” features. These browsers maintain a history of server computer visited in a surfing session. That is, they sace (cache) in local computer’s memory, the url addresses of server computers visited by a user during a surfing session , so that if a user wants to go back to an already visited server later on (in the same surfing session), the link is still available in local computer’s memory -
Browser enable a user to create and maintain a personal list of favorite url adders of server computers that the user is likely to visite in future frequently. -
Unlike FTP and telnet browswr don’t require a user to log into a server computer remotely, and then log out again when the user is finished accessing information stored on server computer.
Q.2 DNS ( domain name system)?
-
DNS is a very well known protocol. -
The DNS protocol works when your computer sends out a DNS
query to a name server to resolve a domain.
The DNS protocol utilises Port 53 for its service. This means that a DNS server listens on Port 53 and expects any client wishing to use the service to use the same port.
-
It is used for resolving host names and domain names to IP
addresses ( or vice versa)
-
The Domain Name System is a 'hierarchically distributed database',
which is a fancy way of saying that its layers are arran ed in a
definite order and that its data is distributed across a wide range of machines (just like the roots of a tree branch out from the main root).
Top-level domains :
Domain Used By
========== ==========
.com Commercial organizations, as in novell.com
.edu Educational organizations, as in ucla.edu
.gov Governmental agencies, as in whitehouse.gov
.mil Military organizations, as in army.mil
.org Nonprofit organizations, as in redcross.org
.net Networking entities, as in nsf.net
.int International organizations, as in nato.int
Q. what is HTML?
A. HYPER TEXT MARK UP LANGUAGE
The language used to develop web pages is called HYPER TEXT MARK UP LANGUAGE(html). HTML is the language interpreted by a web browser. Web pages are called HTML documents. HTML is a set of special codes that can be embedded directly into the text to add formatting and linking information. HTML is specified as tags in an HTML document.
HTML TAGS
Tags are the instructions that are embedded directly into the text of the document. An HTML tag is a signal to a browser that it should do something other than just throw text up on the screen. By convention all HTML tags begin with an open angel bracket (<) and end with an close angel bracket (>).
HTML tags can be of two types:
PAIRED TAGS: A tag is said to be a paired tag if comes with a companion tag, flanks the text. For example <B> tag is a paired tag with its companion tag </B> causes the text contained between them to be rendered in bold. In paired tag the first tag (<B>) is often called the opening tag and the second tag (</B>) is called the closing tag.
The opening tag activates the effect on and the closing tag turns the effect off.
SINGULAR TAGS: The second type of the tag is the singular tag or stand-alone tag. A stand-alone tag does not have a companion tag. For example <BR> tag will insert a line break. This tag does not require any companion tag.
THE STRUCTURE OF HTML PROGRAM
Every HTML program has a rigid structure. The entire web page is enclosed with <HTML> </HTML> tags. Within these tags two distinct sections are created using the <HEAD> </HEAD> tag and the <BODY> </BODY> tags. These sections are described below.
DOCUMENT HEAD:
Information placed in this section is essential to the inner working of the document and has nothing to do with the content of the document. With the exception of the information contained witHin the <TITLE> </TITLE> tags, all the information placed within the <HEAD> </HEAD> tags is not displayed in the browser. It is indicated in the title bar.
<HEAD>
<TITLE>……………… </TITLE>
</HEAD>
DOCUMENT BODY:
The tag used to indicate the start and end of the main body of the textual information are:
<body>
----------
-----------
-------------
</body>
Page defaults like background color, text color can be specified as attribute of the body tag. The attributes that the <BODY> tag takes are:
BGCOLOR: Changes the default background color to whatever color is specified with this tag. The user can specify the a color by name.
BACKGROUND: specifies the name of the gif file that will be used as the background of the document.
TEXT: changes the body text color from its default value to the color specified with this attribute.
Example:
<BODY BACKGROUND=”STARFIED.GIF” TEXT=RED>
NOTE: ALL THE CODE IS WRITTEN INTO A NOTE PAD AND TO SAVE IT WE USE THE FILE EXTENSION .HTML. FOR EXAMPLE: SUKHI.HTML.
LINE BREAKS:
When text needs to start from a new line and not continue on the same line(without skipping a blank line), the <BR> tag is used. This tag simply jumps to the start of the next line.
For example:
Hello<BR> hoe are u<BR> welcome to my site.
Output:
Hello
How are u
Welcome to my site.
EMPHASIZING MATERIAL IN A WEB PAGE
Document pages are usually divided into sections and sub sections , which needs to be emphasized. HTML provides certain heading styles and horizontal rules, which helps break text into logical sections with visual appeal.
Heading Styles: HTML supports six different levels of heading. The highest – level header format is <H1>. And the lowest level is <H6>. All the styles appear in boldface and the size of the heading depends on the level chosen.
For example:
<h3> The early years</h3>
Output:
The early years
Drawing lines: The <HR> tag draws lines and horizontal rules. This tag draws a horizontal line across the whole page, wherever specified. The attributes to the <HR> tag are:
ALIGN: aligns the line on the screen, which is by default aligned to the center of the screen. It has three different values left, right and center.
SIZE: changes the size of the rule.
WIDTH: sets the width of the rule. We can set any no. 1,2,3,-----.
TEXT STYLES:
BOLD: displays the text in bold face.
<B>----------</B>
ITALICS: displays the text in italics.
<I>-----------</I>
UNDERLINED: displays text as underlined.
<U>-----------</U>
CONTROLLING FONT SIZE AND COLOR:
All the text specified within the tags <FONT> and </FONT> will appear in the font, size and color as specified as attributes of the tag <FONT>. The attributes are:
FACE: sets the font to the specified font name.
SIZE: sets the size of the text in numbers by default it is 3.
Color: sets the color of the text.
For example:
<FONT FACE=”TIMES NEW ROMAN” SIZE=6 COLOR=RED>-----------------------------</FONT>
LIST
TYPES OF LISTS
UNORDERED LIST(BULLETS)
An unordered list start with the tag <UL> and ends with </UL>. Each list item starts with the tag <LI>. The attributes that can be specified with <li> are
Type: specifies the type of the bullet.
Type= fillround will give a solid round black bullet.
Type=square will give a solid square black bullet.
For example:
Some of these products include:
<UL TYPE=FILLROUND>
<LI>FLOPPIES
<LI>HARD DISK
<LI>MONITER
</UL>
OUTPUT:
Some of these products include:
FLOPPIES
HARD DISK
MONITER
ORDERED LIST:
An ordered list start with the tag <OL> and ends with </OL>. Each list item starts with the tag <LI>. The attributes that can be specified with <li> are:
Type: controls the numbering scheme to be used.(1, A, a, I,i)
Start: alters the numbering sequence. Can be set to any numeric value.
Value: changes the numbering sequence in the middle of the ordered list. It is to be specified with the <LI> tag.
For example:
Some of these products include:
<OL TYPE=”1” START=3>
<LI>FLOPPIES
<LI VALUE=7>HARD DISK
<LI>MONITER
</OL>
OUTPUT:
Some of these products include:
FLOPPIES
7. HARD DISK
8. MONITER
DEFINITION LIST:
Definition list values appear with in tags <DL> & </DL>.definition lists consist of two parts.
Definition term: appears after the <DT>.
Definition description: appears after the <DD>
FOR EXAMPLE:
<DL>
<DT> KEYBOARD
<DD> AN INPUT DEVICE
<DT> PRINTER
<DD> AN OUTPUT DEVICE
</DL>
OUTPUT:
KEYBOARD
AN INPUT DEVICE
PRINTER
AN OUTPUT DEVICE
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