Archive for February, 2009

HTML stands for Hyper Text Markup Language. It is a markup language that is used to design web pages. HTML is written in the form of tags which are enclosed in angular brackets.HTML elements are the main entities of markup language. Each element has two properties namely attribute and content. Some restrictions are imposed on these properties to make a valid HTML document. There are two tags for an element. One is the starting tag and the other is the end tag. The element attribute is written in the starting tag and the content is placed between these two tags. BUt several elements such as break does not have any content and therefore it does not have any end tag or closing tag. Several types of marks up used in HTML are

HTML - A Markup Language

• Structural Markup: Its main purpose is to define the role of text. Text can also be style sheets.
• Presentation Markup: It defines the appearance of text rather defining its functionality.
• Hypertext Markup: The role of hyper text markup is to join several documents.

Attributes of HTML: One element in HTML can take more than one attribute

The id attribute serves as a identifier for the element. It can be used by cascaded style sheets to determine their presentation properties. It can be used by the web browser to concentrate on a particular document.

The class attribute is used to classify the same elements for different purposes.

Transferring of HTML document

Basically the HTML document is transferred from one system to another like any other file. But two ways are generally preferred:

Over HTTP: The world wide web contains HTML documents which are transferred from a web server to a web browser with the help of Hyper Text Transfer Protocol. The web browser then execute the data with the help of information which was transferred with the document.

HTML e-mail: Two things are required for an HTML e-mail. First is a GUI editor to compose the mail. THE second one is rendering engine to display that message. However this method is rarely used because the HTML e-mail can lead to confusion in spam filters.

HTML Files Naming Conventions

The HTML files have a extension of .htm. It is very much similar to old days operating systems and file systems such as DOS and FAT respectively, which also uses three alphabets for a file extension. At present two flavors of HTML are available. These are XML based HTML and SGML based HTML.

Web Style Sheets provides a way to separate the content structure and style. Web pages designed using style sheets gives complete information about the content and its structure but completely hides its layout or style. The popular languages used for style sheets are Cascaded Style Sheets(CSS) and XSL.

web-style-sheets-for-web-designing

Benefits of style sheets

The advantages of using style sheets in the designing of a web page are:

Speed: In a web site with Cascaded Style Sheets the user will experience a less time in loading a website. The first page of the website will take more time to load because it needs to transfer the style sheets and its content in the memory of browser. But after the completion of first page loading the other pages will be loaded in a very rapid time as the information about the style sheets and its content has been already transferred in the browser memory.

• Maintenance: All of the style sheets can be loaded in one file therefore it requires less maintenance and decreases the chances of human errors as they have to manage a single file only.Also the webpages with style sheets requires less effort for its editing.
• Accessibility: Websites with style sheets technology are displayed in a similar fashion in different browsers(Opera,Safari, Internet Explorer, Mozilla Firefox). If a browser is unable to understand a particular style sheet then it can ignore it and can display the content to the user.
• Customization: THe information about style is stored externally. So if a user intentionally or accidentally disable the content, it will still remain in readable form. The webmasters provides a lot of style sheets by virtue of which the look of a website can be completely changed without any alteration in its content.
• Consistency: The style sheets files contains only the information which a web designer wants to convey. Thus provides consistency in a website by removing all the meaningless things. The other advantage of using style sheet is that the designer does not need to worry about the style properties at the composition time. The properties need to be defined only at the presentation time.

Disadvantages of using style sheets

The usage of style sheets have certain limitations also One such limitation is that the web tools find it difficult to adapt the style sheet specifications. THe other disadvantage is that the use of style sheets make the changes in the semantic vocabulary of the style elements due to which they are changed into a general vocabulary format. So a web master has to define certain elements to convey their meaning.

ASP stands for Active Server Pages. It is first ever server side script engine designed by Microsoft for the Web Pages that are dynamically designed. It was first released as an additional component with Windows 4.0 version. But later on it was included as a free component of Windows 2000 server. An ASP website is easy to program because of the availability of built in objects. The ASP 2.0 version

asp-and-aspnet

contains six built in objects. these are Response,Request, Error, Server, Application and Session. Session for example is an object whose task is to maintain the variables from one page to another page during a cookie session. The ASP webpages are stored in a file with .asp extension. But some companies uses .aspx extension for security purposes. But this extension is provided on a ASP.net page. The active Server pages are designed mostly in VB script BUT other scripts such as Java script and Perl script can also be used.

ASP and its Version

Upto now ASP has releases its three main versions

ASP 1.0 : It was released in 1996 and was an add on component of Internet Information Server(IIS 3.0)

ASP 2.0 : It was released in 1997 and was an add on component of Internet Information Server(IIS 4.0)

ASP 3.0 : It was released in 1996 and was a free component of Internet Information Server(IIS 3.0)

Difference between ASP and ASP.net

Some of the users are confused with these terms. According to them these are two different names of a same technology but both the technolgies are completely different

ASP uses script languages such as Java script, VB script, Perl script while ASP.net can use any of the .net technologies which includes J#,VB.Net, C# etc.

ASP has a maximum of six inbuilt classes while ASP.net can have a minimum of 200 inbuilt classes.

ASP does not contain any component based on server while ASP.net contains Server based components such as Buttons, Text etc.

ASP does not provide Page level transactions feature while ASP.net provides this feature.

ASP cannot be used for event driven processing while ASP.net can be used for event driven processing