CS1401-INTERNET COMPUTING 2 units Question Bank with Answers Unit-1 FUNDAMENTALS Part-A 1. What are the sequences of steps for each HTTP request from a client to the server? 1. Making the connection 2. Making a request 3. The response 4. Closing the connection 2. What is meant by Stateless Connection? When a web server receives a HTTP request from a web browser it evaluates the request and returns the requested document, if it exists, and then breaks the HTTP connection. This document is preceded by the response header, which has details about how to display the document that will be sent by the server. Each time a request is made to the server, it is as if there was no prior connection and each request can yield only a single document. This is known as Stateless Connection. 3. Difference between GET and POST request?
Cached History
Restrictions on data length Restrictions on data type
Security Visibility
GET Can be cached Parameters remain in browser history Yes, when sending data, the GET method adds the data to the URL; and the length of a URL is limited (maximum URL length is 2048 characters) Only ASCII characters allowed GET is less secure compared to POST because data sent is part of the URL Data is visible to everyone in the URL
4. Write a JavaScript to display a Clock.
POST Not cached Parameters are not saved in browser history
No restrictions No restrictions. Binary data is also allowed POST is a little safer than GET because the parameters are not stored in browser history or in web server logs Data is not displayed in the URL
5. Write a VBScript to remove leading or trailing spaces from string?
6. Write a java script program using switch case statement to extract the day from the current date and display what day it is.
7. What is the difference between node and host? A node is any addressable device connected to a network whereas the host is a more specific descriptor that refers to a networked general-purpose computer rather than a single purpose device (such as a printer). 8. Compare HTML and DHTML HTML 1. It is referred as a static HTML and static in nature. 2.A plain page without any styles and Scripts called as HTML.
3.HTML sites will be slow upon client-side technologies. 4.HTML pages does not require any processing from browser DHTML 1.It is referred as a dynamic HTML and dynamic in nature. 2.A page with HTML, CSS, DOM and Scripts called as DHTML. 3.DHTML sites will be fast enough upon client-side technologies. 4.DHTML requires processing from browser which changes its look and feel 9. What are the various Internet Application Protocols? HTTP(Hyper Text Transfer Protocol) HTTPS(Secure Hyper Text Transfer Protocol) FTP(File Transfer Protocol) SMTP(Simple Mail Transfer Protocol) ICMP(Internet Control Message Protocol) 10. Why we need Client Side Scripting? Client-side scripting is code that exists inside the client’s HTML page. This code will be processed on the client machine and the HTML page will NOT perform a Post Back to the web-server. Traditionally, client-side scripting is used for page navigation, data validation and formatting. The user’s actions will result in an immediate response because they don't require a trip to the server. Part-B 11. Write simple HTML program to illustrate the usage of forms and inputs
Student Registration Form
Please fill all the fields
output form
12. Explain the class of internet addresses and the method of retrieving the data with URL. Definition of URL: We can retrieve data by using the address of the file. This address is called a Uniform Resource Locator(URL). The Address box of the browser shows the URL of the currently displayed document. We can type a URL into the address box and can get the file we wanted. Syntax protocol://domain:port/path?query_string#fragment_id
Explanation: In the same way as each host computer has a unique IP address, every data file or document on the Internet also has a unique address called a URL. The URL consists of three parts: the protocol, the domain name and the path. The protocol, as discussed earlier, is the set of rules which the computer follows in order to communicate with other computers. It lets the computer know how to process the information it receives. If the protocol is http:// , for example, the computer knows it will be processing a World Wide Web document.
The domain name is the Internet address of the computer (server) that is hosting the site and storing the documents. This domain name may be expressed as an IP address. The path is the directory and file specification: it lets the computer know which directory and file to access after connecting to the server. The path is not a required elements, but if you know the path, it will take you directly to the desired file or document. The path is also part of the URL which changes frequently. For example, http:// is the protocol. This lets you know that you are retrieving a World Wide Web document and lets the computer know how to process the hypertext file it is receiving. www.linccweb.org/ is the domain name, the address of the computer that is hositng the web page. E-resources.asp provides the path to the specific page you want; in this case, the name of the file (eresources.asp) that provides links to electronic database. Example http:// www.linccweb.org/eresources.asp Retrieving data with url program: // Demonstrate URL Import java.net *; Class URL Demo{ Public static void main(String args[])throws malformed URL exception { URL hp = new URL(“http:// www.ijcsns.org/downloads”); System.out.println(“protocol”+hp.get protocol()); System.out.println(“port” hp.get port()); System.out.println(“host”: + hp.get host()); System.out.println(“file”: +hp.get files()); System.out.println(“ext”: +hp.to external form()); } } 13. a) Why is meant by a function procedure in VB script? Write a VB Script function procedure to receive the current time and display the time along with a.m or p.m A Function procedure: is a series of statements, enclosed by the Function and End Function statements can perform actions and can return a value can take arguments that are passed to it by a calling procedure without arguments, must include an empty set of parentheses () returns a value by assigning a value to its name
Function myfunction() some statements myfunction=some value End Function (Or) Function myfunction(argument1,argument2) some statements myfunction=some value End Function
A Function procedure can return a result.
b) Write a script in java for calculating the total marks of 6 subjects for 60 students. try to count 14. Explain in detail about Cascading Style Sheets with suitable examples. Definition of CSS: Cascading style sheets (css) are rules or styles for organizing the layout of an HTML document including its color, typefaces, margins, links and other formatting elements.
Types of CSS Inline Style with example Internal Style with example External style with example Inline Style There are four ways of adding styles to a web page Embed style sheet within the HEAD tags of the HTML document. Link to an external style sheet from the HTML document. Import an external style sheet into the document. In-line style sheet added into the middle of the HTML document. Local (in-line) style sheet declarations, specific to a single instances on a page can be used instead of tags to specify font size, color, and typeface and to define margins, leading, etc. The inline style attribute is supported by most tags the allows the author to modify the properties of individual tagged regions document. An example of a tag with a style attribute is:
This is a heading
There are other ways to make the same changes to this heading, for example, use the font tag to modify the font properties
This is a heading
. There are many ways to define in-line style sheet. However, it is now generally accepted as better to use style attributes rather than other tags for changing the rendering of text and other document entities. The reason for text and other document entities. The reason for having styles is to easily define modification to rendering attributes that apply to parts of a document, in entire documents, or even an entire website.
Internal Style Global (embedded) style sheet declarations, applicable to an entire Document, are defined within the tags, which precede the tag in the HTML document and are usually placed in the header. To embed a global style sheet in the HTML document, the following Syntax is used Title [DOCUMENT BODY GOES HERE] External style Linked style sheet declarations use a single style sheet (in a separate file from HTML documents, saved with the .css suffix) to define multiple pages. They can be accessed by multiple files with a single link tag, ensuring consistency in a website and making it very easy to make global changes/updates. These external style sheets offer several benefits. o Web developers and web managers may share style sheets across a number of documents or sites. o The designers can changes style sheet without affecting the document. The users also lead individual style sheets when they are separately available. o To access them use the in the head section. As the following syntax suggests. Advantages and Disadvantages of CSS CSS saves time: when most of us first learn HTML, we are taught to set the font face, size, color, style, etc. Every time it occurs on a page. This means we find ourselves typing ( or copying and pasting) the same thing again and again. With css, you only have to specify the details once. Css will automatically apply the elements. Css will automatically apply the specified styles whenever that element(s) occurs. Pages load faster: less code means faster download times. Easy maintenance: to change the style of an element, you only have to make an edit in one place. Superior styles to HTML: css has a much wider array of attributes than HTML Disadvantage Browser compatability: the two main browsers ( netscape and internet explorer) , have varying levels of complains with style sheets. This means that some style sheet features are supported and some are not.
15. How will you specify a frame layout? Explain. Introduction to frames HTML frames allow authors to present documents in multiple views, which may be independent windows or subwindows. Multiple views offer designers a way to keep certain information visible, while other views are scrolled or replaced. For example, within the same window, one frame might display a static banner, a second a navigation menu, and a third the main document that can be scrolled though or replaced by navigating in the second frame. Here is a simple frame document: A simple frameset document
If the user agent can't display frames or is configured not to, it will render the contents of the NOFRAMES element. Layout of frames An HTML document that describes frame layout (called a frameset document) has a different makeup than an HTML document without frames. A standard document has one HEAD section and one BODY. A frameset document has a HEAD, and a FRAMESET in place of the BODY. The FRAMESET section of a document specifies the layout of views in the main user agent window. In addition, the FRAMESET section can contain a NOFRAMES element to provide alternate content for user agents that do not support frames or are configured not to display frames. Elements that might normally be placed in the BODY element must not appear before the first FRAMESET element or the FRAMESET will be ignored. A frameset document Sample Output: -----------------------------------------|Frame 1 |Frame 3 |Frame 4 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | -------------| | | |Frame 2 | | | | | | | | | | | ------------------------------------------
16. Write short notes on the scripting languages Java Script and VB Script with examples. Need for Client Side Scripting: Client-side scripting, can be embedded into the page on the client’s browser. This script will allow the client’s browser to alleviate some of the burden on your web server when running a web application. Client-side scripting is source code that is executed on the client’s browser instead of the web-server, and allows for the creation of faster and more responsive web applications. The two main benefits of client-side scripting are: •
The user’s actions will result in an immediate response because they don't require a trip to the
•
server.
Fewer resources are used and needed on the web-server.
JavaScript : • It is a programming language. • It is an interpreted language. • It is object-based programming. • It is widely used and supported • It is accessible to the beginner. 2.Advantages of JavaScript • Speed. Being client-side, JavaScript is very fast because any code functions can be run immediately instead of having to contact the server and wait for an answer. •
Simplicity. JavaScript is relatively simple to learn and implement.
•
Versatility. JavaScript can be inserted into any web page regardless of the file extension. JavaScript can also be used inside scripts written in other languages such as Perl and PHP.
• •
Server Load. Being client-side reduces the demand on the website server. 3. Disadvantages of JavaScript Security. Because the code executes on the users' computer, in some cases it can be exploited for malicious purposes. This is one reason some people choose to disable JavaScript.
•
Reliance on End User. JavaScript is sometimes interpreted differently by different browsers. Whereas server-side scripts will always produce the same output, client-side scripts can be a little un predictable. Don't be overly concerned by this though - as long as you test your script in all the major browsers you should be safe.
My First JavaScript
This is a paragraph.
OUTPUT; My First JavaScript This is a paragraph.
VBScript: 1.VBScript is a scripting language 2.A scripting language is a lightweight programming language 3.VBScript is a light version of Microsoft's programming language Visual Basic Advantages of VBScript: • No special installation required •
Popular on windows
•
Flexible for the Visual Basic programmer, they did not need any new learning to master in VBScript.
Disadvantages of VBScript: • Does not provide cross platform support. •
No specific way to provide multi line comment
OUTPUT: This is my first VBScript!
Unit-2 Server Side Programming
PART-A 1. What is meant by loop Back address? 127.0.0.1 is the loopback address in IP. Loopback is a test mechanism of network adapters. Messages sent to 127.0.0.1 do not get delivered to the network. Instead, the adapter intercepts all loopback messages and returns them to the sending application. IP applications often use this feature to test the behaviour of their network interface. 2. What are the two commonly used request methods? The two most common request methods used are GET and POST. GET - Requests data from a specified resource POST - Submits data to be processed to a specified resource 3. What is the significance of servlet container? To deploy and run a servlet, a web container must be used. A web container (also known as a servlet container) is essentially the component of a web server that interacts with the servlets. The web container is responsible for managing the lifecycle of servlets, mapping a URL to a particular servlet and ensuring that the URL requester has the correct access rights. 4. How to track a user session in servlets? There are four typical solutions to this problem: cookies, URL rewriting, hidden form fields and Session tracking APIs. 5. What is the usage of java servlets? The servlet is a Java programming language class used to extend the capabilities of a server. Although servlets can respond to any types of requests, they are commonly used to extend the applications hosted by web servers, so they can be thought of as Java Applets that run on servers instead of in web browsers. (OR) o o o o
Servlets are most often used to Process or store data that was submitted from an HTML form Provide dynamic content such as the results of a database query Manage state information that does not exist in the stateless HTTP protocol, such as filling the articles into the shopping cart of the appropriate customer o Handling HTTP client requests o Capable of serving multiple clients concurrently 6. Why build web page dynamically? o The Web page is based on data submitted by the user.
o E.g., results page from search engines and order confirmation pages at on-line stores o The Web page is derived from data that changes frequently. E.g., a weather report or news headlines page o The Web page uses information from databases or other server-side sources E.g., an e-commerce site could use a servlet to build a Web page that lists the current price and availability of each item that is for sale. 7. Give some examples for web server and web browser? Web Servers: Apache HTTP Server Microsoft Internet Information Services (IIS) Sun Java System Web Server Apache Tomcat JBoss Web browsers: Internet Explorer Mozilla Firefox Opera Safari Google Chrome 8. What is the motive of JSP? JSP is widely used for developing dynamic web sites. JSP is used for creating database driven web applications because it provides superior server side scripting support. Simplifies the process of development Portability Because of Efficiency Independency of Layers 9. What are the return values of getParameter values method of the Http servlet Request? Returns the values of the specified parameter for the request as an array of strings, or null if the named parameter does not exist.
10. What is the use of JSP scriptlets? A JSP scriptlet is used to contain any code fragment that is valid for the scripting language used in a page. The syntax for a scriptlet is as follows: <% scripting-language-statements %>
PART-B 1. How can you use the servlet session tracking API to keep track of visitors as they move around at your site with example. The Need for Session Tracking
HTTP is a “stateless” protocol: each time a client retrieves a Web page, the client opens a separate connection to the Web server and the server does not automatically maintain contextual information about the client. Even with servers that support persistent (keep-alive) HTTP connections and keep sockets open for multiple client requests that occur in rapid succession, there is no built-in support for maintaining contextual information. This lack of context causes a number of difficulties. For example, when clients at an online store add an item to their shopping carts. Similarly, when clients decide to proceed to checkout, how can the server determine which previously created shopping carts are theirs? These questions seem very simple, yet, because of the inadequacies of HTTP, answering them is surprisingly complicated. There are three typical solutions to this problem: cookies, URL rewriting, and hidden form fields.
Our example tracks the number of visits for each unique visitor. If this is a first time visit, the servlet creates an accessCount of Integer Integer Type and assigns it to the Session. If the user has visited before,the servlet extracts the accessCount and increments it, and also assigns it to the Session. Servlet also displays basic information regarding the session including creation time and time of last access.
package coreservlets; import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.net.*; import java.util.*; public class ShowSession extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html"); PrintWriter out = response.getWriter(); String title = "Session Tracking Example"; HttpSession session = request.getSession(true); String heading; Integer accessCount = (Integer)session.getAttribute("accessCount"); if (accessCount == null) { // new user accessCount = new Integer(0); heading = "Welcome, Newcomer"; } else { // returning user heading = "Welcome Back"; accessCount = new Integer(accessCount.intValue() + 1); } // Integer is an immutable (nonmodifiable) data structure. So, you can not modify the old one in-place. //Instead you have to to allocate a new one and redo setAttribute. session.putAttribute("accessCount", accessCount); out.println(ServletUtilities.headWithTitle(title) + "\n" + "
" + heading + "
\n" + "
Information on Your Session:
\n" + "
\n" + "
\n" +
Info Type
Value\n" + "
\n" + "
ID\n" + "
" + session.getId() + "\n" + "
\n" + "
Creation Time\n" + "
" + new Date(session.getCreationTime()) + "\n" + "
\n" + "
Time of Last Access\n" + "
" + new Date(session.getLastAccessedTime()) + "\n" + "
\n" + "
Number of Previous Accesses\n" + "
" + accessCount + "\n" + "
"+ "
\n" + ""); } /** Handle GET and POST requests identically. */ public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); }
} Sample Output:
2. Give detailed notes on servlet chaining and communications with proper example. 16 SERVLET CHAINING
• •
Servlets cooperate to create content Multiple servlets in a chain – request parameters supplied to first servlet – output piped to successive servlets – last servlet in chain sends output to client
Servlet Chaining Can be Used to
• • •
Quickly change appearance of a page, group of pages, or type of content – suppress
CS1401-IC-UNIT-1&2_NoRestriction.pdf
... Scripts called as HTML. Whoops! There was a problem loading this page. CS1401-IC-UNIT-1&2_NoRestriction.pdf. CS1401-IC-UNIT-1&2_NoRestriction.pdf.
