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Introduction to Protocol and Web Pages

HTTP Protocol
HyperText Tranfer Protocol (HTTP) is the standard protocol which is important data communication for the in the World Wide Web. HTTP's main functions as a request-response protocol in the client-server computing Model.(google) In HTTP, a web browser acts as a client while an application running on a computer hosting a website functions as a server. The client submits an HTTP request message to the server.(forums.asp.net) The server, which stores content, or provides resources, such as HTML files or performs other functions on behalf of the client, returns a response message to the client.(forums.asp.net) A response contains complete response status information about the request and may contain any content requested by the client.(w3.org)

It is alos known as stateless, you send request and it responds does not maintain any state. (ASPbook) We can use to maintain the state:

  • Session Object in the server side
  • Cookies in the client side.
  • Hidden variables in the form
Static and Dynamic Pages
Static Web Pages
A static web page is a web page that is delivered to the user exactly as stored, in contrast to dynamic web pages which are generated by a web application.(wikipedia)

A static web page displays the same information for all users, from all contexts, subject to modern capabilities of a web server to negotiate content-type or language of the document where such versions are available and the server is configured to do so.(wikipedia)

Static web pages are often HTML documents stored as files in the file system and made available by the web server over HTTP.(wikipedia)

Advantages:
  • Programming skills are not required to create a static page.
  • Inherently publicly cacheable .i.e. a cached copy can be shown to anyone.
  • No particular hosting requirements are necessary.(scribd)
  • Can be viewed directly by a web browser without needing a web server or application server
Disadvantages:
  • Any personalization or interactivity has to run client-side ie. in the browser, which is restricting.(scribd)
  • Maintaining large numbers of static pages as files can be impractical without automated tools.
Dynamic Web pages
A dynamic web page is a kind of web page that has been prepared with recent information, for each individual viewing. It changes with the time. For ex. News content, events. The content of the site changes when the user logs in and logs out. Page contents are displayed according to the location of the user. In facebook, you can see suggestions to add friends since it knows your friends and those are mostly friend of your friends. Facebook gets updated with recent feeds etc.

Dynamic web pages can be created in two ways
a)Client-Side Scripting
Using client-side scripting to change interface behaviors within a specific web page, in response to mouse or keyboard actions or at specified timing events.(scribd) In this case, the dynamic behavior occurs within the presentation. (scribd)

Client-Side scripting languages like JavaScript or Actionscript, used for DHTML and Flash technologies respectively, are frequently used to play with the media types like sound, animations, changing text, etc. of the presentation

The Client-side content is generated on the user's computer. The web browser retrieves a page from the server, then processes the code embedded in the page often written in JavaScript and displays the retrieved page's content to the user. (scribd)

b)Server-Side Scripting
A program running on the web server is used to change the web content on various web pages, or to adjust the sequence of or reload of the web pages.(scribd) Server responses may be determined by such conditions as data in a posted HTML form, parameters in the URL, the type of browser being used, the passage of time, or a database or server state.(optionsface.blogspot) Such web pages are often created with the help of server-side languages such as ASP, PHP, JSP etc.

c)Combined Client Side and Server Side
Ajax is a web development technique for dynamically interchanging content with the server-side, without reloading the web page.(scribd) Google Maps is an example of a web application that uses Ajax techniques and database.(optionsface.blogspot)

Disadvantages
Search engines work by creating indexes of published HTML web pages that were, initially, "static".(optionsface.blogspot) With the advent of dynamic web pages, often created from a private database, the content is less visible. Unless this content is duplicated in some way .for example, as a series of extra static pages on the same site, a search may not find the information it is looking for. It is unreasonable to expect generalized web search engines to be able to access complex database structures, some of which in any case may be secure.(optionsface.blogspot)

Introduction to ASP
Microsoft Active Server Pages (ASP) is a server-side scripting technology created by Microsoft to ease the development of interactive Web applications.We can manage the content of any page and such dynamic code or content with server side scripting language like ASP , for the web browsers can be generated based on various conditions.

ASP engine performs code processing and then send the codes to users browser and waits until the next request. We should not expect ASP to perform some tasks which are likely to happen at the client browser end. This will be clear when we determine some of the task and where the task is to be completed and which script will take care of it.

ASP also provides solutions for transaction processing and managing session state. ASP is one of the most successful language used in web development.

Benefits and Application of ASP
  • It can dynamically edit, change, or add any content of a Web page
  • It can respond to user queries or data submitted from HTML forms
  • It can access any data or databases and return the results to a browser
  • ASP can be used to customize a Web page to make it more useful for individual users
  • ASP also provides security
  • Clever ASP programming can minimize the network traffic
Problems with traditional ASP
  1. Interpreted and Loosely-Typed Code
    ASP scripting code is usually written in languages such as JScript or VBScript. (scribd)The script-execution engine that Active Server Pages relies on interprets code line by line, every time the page is called.(dotnet-programming) In addition, although variables are supported, they are all loosely typed as variants and bound to particular types only when the code is run.(dotnet-programming) Both these factors impede performance, and late binding of types makes it harder to catch errors when you are writing code.(dotnet-programming)
  2. Mixes layout (HTML) and logic (scripting code)
    ASP files frequently combine script code with HTML. This results in ASP scripts that are lengthy, difficult to read, and switch frequently between code and HTML which can cause problems when content must be kept separate from business logic.(dotnet-programming)
  3. Limited Development and Debugging Tools
    Microsoft Visual InterDev, Macromedia Visual UltraDev, and other tools have attempted to increase the productivity of ASP programmers by providing graphical development environments.(aspbook) But, these tools never achieved the comfort provided by Microsoft Windows application development tools, such as Visual Basic or Microsoft Access. Debugging is an unavoidable part of any software development process, and the debugging tools for ASP have been minimal.(programmerworld.net)
  4. No real state management
    Session state is only maintained if the client browser supports cookies.(scribd) Session state information can only be held by using the ASP Session object. And you have to implement additional code if you, for example, want to identify a user.(optionsface.blogspot)
  5. Update files only when a server is down
    You can updated files or changes to the web application only when the server is down. Otherwise, it is like pulling the rug from under your application's feet, because the components may be in use (and locked) and must be registered.(scribd)
  6. Obscure Configuration Settings
    The configuration information for an ASP web application (such as session state and server timeouts) is stored in the IIS metabase. Because the metabase is stored in a proprietary format, it can only be modified on the server machine with utilities such as the Internet Service Manager. (optionsface.blogspot)With limited support for programmatically manipulating or extracting these settings, it is often an arduous task to port an ASP application from one server to another.(optionsface.blogspot)

 

Reference
  • ASPbook. <https://books.google.com.np/books?id=8kySzn3YfuEC&pg=PA129&lpg=PA129&dq=by+the+client.+It+is+alos+known+as+stateless,+you+send+request&source=bl&ots=CJL75tq1sz&sig=IIh6m3fWQ3UnMZLKs1m-ypD7Q-0&hl=en&sa=X&redir_esc=y#v=onepage&q=by the client. It is>.
  • aspbook. <http://hesab.net/book/asp.net/IntrotoASPNET.pdf>.
  • dotnet-programming. <http://dotnet-programming.blogspot.com/>.
  • optionsface.blogspot. <http://optionsface.blogspot.com/2011/04/introducing-about-website.html>.
  • programmerworld.net. <http://www.programmerworld.net/articles/asp_net/aspintro.php>.
  • scribd. <https://www.scribd.com/document/86854821/ASP>.

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