Internet Technologies Questions & Answers
1、 What is HTTP? How does it work (in basic terms)?
HTTP: (HyperText Transport Protocol) The communications protocol used to connect to servers on the World Wide Web. Its primary function is to establish a connection with a Web server and transmit HTML pages to the client browser. Addresses of Web sites begin with an http:// prefix; however, Web browsers typically default to the HTTP protocol. Web browsers communicate with Web servers via the TCP/IP protocol. The browser sends HTTP requests to the server, which responds with HTML pages and possibly additional programs in the form of ActiveX controls or Java applets.
2、 What is a CGI program? How does one get invoked?
CGI(Common Gateway Interface script) A small program written in a language such as Perl, Tcl, C or C++ that functions as the glue between HTML pages and other programs on the Web server. For example, a CGI script would allow search data entered on a Web page to be sent to the DBMS (database management system) for lookup. It would also format the results of that search as an HTML page and send it back to the user. The CGI script resides in the server and obtains the data from the user via environment variables that the Web server makes available to it.
CGI scripts have been the initial mechanism used to make Web sites interact with databases and other applications. However, as the Web evolved, server-side processing methods have been developed that are more efficient and easier to program. For example, Microsoft promotes its Active Server Pages (ASPs) for its Windows Web servers, and Sun/Netscape nurtures its Java roots with JavaServer Pages (JSPs) and servlets
3、 What is the difference between GET and POST methods of submitting form data?
get-- This has a limit as to number of characters that it can pass. In get the request is sent in the the form of a query string from the web browser to the web server. The max. no. of characters that can be passed are 255. Since the request is sent in the query string that is visible in the address bar of the web browser, this method is not suited for passing confidential info. such as passwords/credit card no's etc.
post-- There is no such limit on the no. of characters that can be passed at a time as the request is passed in the body of the message. So this is useful for passing confidential data. Also, one can pass any length of info. to the server.
4、 What is "URL Encoding"?
URL Encoding is a method by which a string is converted into a format which is suitable for HTTP URL.
Example : Server.URLEncode("sitename=imilap")
Results is sitename%3Dimilap. = is converted into characters which can be used in the URL
5、 What is an HTML "entity"?
Character entity references, or entities for short, provide a method of entering characters that cannot be expressed in the document's character encoding or that cannot easily be entered on a keyboard. Entities are case-sensitive and take the form &name;. Examples of entities include © for the copyright symbol and Α for the Greek capital letter alpha.
6、 How can you do a "redirect" to another page?
This is easily achieved using the Meta tag as below
<META HTTP-EQUIV="Refresh" CONTENT="3;URL=http://www.redirect.to.com">
But I think there are 2 aspects of the problem, redirect from the client side or the server side. As to the client side, if we are using VBScript, just call the navigate method of window object is OK, if not, we can set the window object’s location.href property to the URL of the target page. As to the server side, if differs from languages to languages.
7、 What web servers do you have experience with? Apache? IIS?
8、 How does an XML DTD work, and what are some of its limitations?
XML DTD: Extensible Markup Language Document Type Definition. It is to define the legal building blocks of an XML document. It defines the document structure with a list of legal elements. A DTD can be declared inline in your XML document, or as an external reference.
The drawbacks of DTD:
1) DTD doesn’t comply with the XML syntax,
2) The data types of DTD is limited,
3) DTD is not extensible,
4) DTD doesn’t support namespace.
9、 What are session variables?
When a user logs in a web site a session is created. Session variables are a variable which remain active throughout this session.
The use of Session variables is to store information pertinent to that particular session. Example: user preferences etc.
10、 What problems do the vendors of ODBC Technology face with ASP/ADO?
ADO's apartment threaded, and ASP doesn't support threading at all.
The main problem would be locking unnecessarily or dead-locking when multiple requests are made thru the same connection object.
11、 What are the three tags of a form tag in HTML form?
ACTION, METHOD, Target and EncType (encoding type)
12、 What are the two tags for framesets?
Frameset, frame and noframes. Example:
<frameset framespacing="0" border="false" frameborder="0" rows="95,*">
<frame name="banner" scrolling="no" noresize target="contents" src="indianlook_top.html">
<frame name="main" src="http://www.imilap.com">
<noframes>
<p>This page uses frames, but your browser doesn't support them.
</noframes>
</frameset>
13、 How do you create Drop Down Combos in HTML?
Using Select tag. Example:
<select name="gender">
<option value="0" SELECTED>Male</option>
<option value="1" >Female</option>
</select>
14、 In DHTML what is the difference between FontSize and Font Size?
FontSize is a property, Font Size is a style.
15、 What is the tag CodeBase and why do we use it?
After writing and compiling a Java applet, you can display it in a web page by using the APPLET tag. The CODE attribute specifies the name of the Java applet to run. The CODEBASE attribute specifies the subdirectory or folder containing the Java applet. You can use PARAM tags between the <APPLET> and </APPLET> tags to provide information about parameters, or arguments, to be used by the Java applet.
Syntax
<APPLET
CODE="classFileName"
CODEBASE="classFileDirectory"
ARCHIVE="archiveFile"
ALT="altText"
ALIGN="LEFT"|"RIGHT"|"TOP"|"ABSMIDDLE"|"ABSBOTTOM"| "TEXTTOP"| "MIDDLE" | "BASELINE" | "BOTTOM"
HEIGHT="height"
WIDTH="width"
HSPACE="horizMargin"
VSPACE="vertMargin"
NAME="value"
>
<PARAM ...>
</APPLET>
The CODE attribute is required (otherwise there is no applet to run). Netscape Navigator 3 and Navigator 4 can display applets if the WIDTH and HEIGHT attributes are omitted, but some other browsers cannot, so for best results you should always include the WIDTH and HEIGHT attributes.
CODE ="classFileName"
specifies the filename of the applet to load. All Java class files end with a .class extension (for example, myApplet.class). Many browsers will display the applet correctly even if you omit the .class extension in the filename.
CODEBASE="classFileDirectory"
is the directory containing the applet class file and any resources the applet needs. The value is a URL for an absolute or a relative pathname. An absolute URL is used as is without modification and is not affected by the document's BASE tag. A relative CODEBASE attribute is relative to the document's base URL defined by the BASE tag. If the document does not define a BASE tag, it is relative to the directory containing the HTML file.
For short, the code property indicates the Qualified Class Name (including package name), ending with .class or not is both OK; the codebase is the well known classpath!
16、 Walk me through the OSI seven-layer model, then explain at what layer a switch, router and hub all operates.
7. Application layer
6. presentation layer
5. Session layer
4. Transport layer
3. Network layer
2. Datalink layer
1. Physical layer
A hub is a physical layer device providing absolute NO intelligence. A switch is a data link layer device which isolates collision domains vs. routers which isolate broadcast domains, giving each connection to a switch a "private" connecting (no collisions/contention). Think of a switch as a multi-port bridge of sorts, allocation a time slice to each connection, but very quickly.
17、 Describe how DNS works. Describe the difference between a resolver and an authoritative master server.
18、 Describe TCP/IP and it's components. What is ARP/RARP? What does a TCP/IP packet looks like?
Address Resolution Protocol (ARP) performs IP address-to-Media Access Control (MAC) address resolution for outgoing packets.
19、 Describe the process that happens when you click a link in your web browser to fetch another web page.
20、 How would you design the web page for a company that sells screws?
How can you have different number of cells for each row of a table?
Its just sufficient to give the number of column<td> tags within the row tags ... and its fine if the cells are varying within each rows.
Colspan will help you keep the alignment of your overall table, that is avoids the step or zig-zag pattern due to different no. of cells in different rows.
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