面试题与答案

ASP stands for Active Server Pages. It is a server side technology which is used to display dynamic content on web pages. For example you could write code that would give your visitors different information, different images or even a totally different page depending on what browser version they are using.

Writing codes within the Tag

Virtual directories are aliases for directory paths on the server. It allows moving files on the disk between different folders, drives or even servers without changing the structure of web pages. It avoids typing an extremely long URL each time to access an ASP page.

VBScript : REM & �(apostrophe)
JavaScript : // (single line comment)
/* */ (Multi-line comments)

VBScript

Variant is the default data type in VBScript, which can store a value of any type.

Variable is a memory location through which the actual values are stored/retrieved. Its value can be changed.

Up to 60 dimensions.

This collection stores any values that are provided in the URL. This can be generated by three methods:
By clicking on an anchor tag
By sending a form to the server by the GET method
Through user-typed HTTP address

It allows you to extract data sent to the server using a GET request.

The two attributes are ACTION and METHOD
The ACTION gives the name of the ASP file that should be opened next by which this file can access the information given in the form The METHOD determines which of the two ways (POST or GET) the browser can send the information to the server

The Session Object has only one method, which is Abandon. It destroys all the objects stored in a Session Object and releases the server resources they occupied.

The ServerVariables collection holds the entire HTTP headers and also additional items of information about the server.

The main difference is that the Querystring collection gets appended to a URL.

The Form collection holds the values of the form elements submitted with the POST method. This is the only way to generate a Form collection.

The Dictionary object, the FileSystemObject object, TextStream object.

The browser makes a HTTP request; the server gives a HTTP response to the browser and the browser converts into a HTML page.

The browser makes a HTTP request; the server does the processing and gives a HTML response to the browser.

Specify

Shares information among users of an application. Gives a notification when an application starts or ends.

Scripts executed only by the browser without contacting the server is called client-side script. It is browser dependent. The scripting code is visible to the user and hence not secure. Scripts executed by the web server and processed by the server is called server-side script.

Response.Write

POST METHOD:
The POST method generates a FORM collection, which is sent as a HTTP request body. All the values typed in the form will be stored in the FORM collection.
GET METHOD:
The GET method sends information by appending it to the URL (with a question mark) and stored as A Querystring collection. The Querystring collection is passed to the server as name/value pair.
The length of the URL should be less than 255 characters.

Only one global.asa file and it�s placed in the virtual directory�s root.

Only one global.asa file and it�s placed in the virtual directory�s root.

Objects that can enhance the application are known as the Scripting Objects.

NOT, AND, OR, XOR, EQV, IMP

Name it�s properties and methods.

Local variables lifetime ends when the Procedure ends. Global variables lifetime begins at the start of the script and ends at the end of the script and it can be used by any procedure within the script. Declaring a variable by using the keyword PRIVATE makes the variable global within the script, but if declared using PUBLIC, then all scripts can refer the variable.

JavaScript

It�s a method by which web pages can be built and generally used for formatting and linking text.

It�s a Computer that provides Web services on the Internet or on a local Intranet. It is designed to locate, address and send out simple HTML pages to all other users who access these pages.

It stores information about a User�s session. Gives a notification when a user session begins or ends.

It provides extra information by which it makes the site easier to manage. It can include text files using the #include statement, retrieve the size and last modification date of a file, defines how variables and error messages are displayed and inserts the values of HTTP variables in the page sent back to the browser.

It provides access to the physical file system of the web server. It gets and manipulates information about all drives in a server, folders and sub-folders on a drive and files inside a folder.

It permits to create more interactive Web Pages. Validation, formatting of web pages can be done. VBScript, JavaScript are some examples.

It lets you store and retrieve information in a flexible data structure. Each value or information stored in a Dictionary is associated with a key through which the information can be retrieved.

It is text file that contains details about an ASP application, such as when it should begin and end.

It is a Text File that contains the combination of the following:
Text
HTML tags
Script Commands

It controls the information sent to the user. The various methods are:
Response.Write - Sends information directly to a browser
Response.Redirect - Directs a user to a URL other than the requested URL
Response.ContentType - Controls the type of content sent
Response.Cookies - Sets cookie values
Response.Buffer - To Buffer information

It can be up to 255 characters Must start with an alphabet Must not contain an embedded period or full-stop

It allows you to access(read/write) the contents of text files stored on the web server.

IIS is a Web Server that provides Web services, not only for web pages but also for ftp sites and video and audio services. It integrates with the database facilities of SQL Server.

Gets information from the user. It has five collections by which values can be accessed. They are: Query string, Form, Cookies, Server Variables & Client Certificate.

EMPTY: has no value
NULL: Value does not exist (conjunction with database)
OBJECT:

Cookies are text files that store information about the user by which the web server identifies and marks each different visitor to a web site and determines where a user has been before. A cookie can store information only when the user sends it. Individual cookies are limited to 4KB of data. The maximum number of cookies allowed is 300.
Cookies are stored on client�s machine.

Cookie collection does not have the Count property. Cookies can have multiple values for the same cookie name but each value can be referred using a key whereas in a Form/Query string cookie each value has to be referred using an index value.

Controls the ASP execution environment. It can set the amount of time script can run before an error occurs. Converts a virtual path to a physical path on the server. Takes a user supplied string and encode it into proper format for a URL string.

Collection is a set of name/value pairs where the information supplied by the client is stored.

By setting its Expires property to any date prior to today Response.Cookies("cookie name"). Expires = Date 1.

Buffer controls the HTML output stream manually.

ASP provides scripting engines that execute the corresponding scripting languages on the server side. Scripts should be encoded within the Delimiters.

ASP is a server side-scripting environment for building dynamic and interactive web pages. Since the scripts run on the server side, the web server does all the processing.

Arrays are variables that store items of similar information.DIM ARRAY1(4) (declares an array with the name array1 with 5 elements)

Application-scope means that variables (and objects) can be accessed from any ASP pages that is part of the application.

An area of a web site available only to a set of registered visitors.

Static HTML Browser uses HTTP to request HTML file from the Web Server
Dynamic HTML Browser uses HTTP to request an executable application rather than a Static HTML file

SessionID returns the session identification number for each user.
Timeout sets the timeout period assigned to the Session object for any application, in minutes.
CodePage determines the code page that will be used to display content.
LCID a locale identifier, which determines time zone and language, rules for the system

Session _OnStart This event will be fired when a new user begins a session with the web site.
Session_OnEnd This event is called whenever a session terminates.

Request Object
Response Object
Server Object
Session Object
Application Object

Minimizes network traffic by limiting the need for the browser and server to talk to each other
Makes for quicker loading time since HTML pages are only downloaded
Allows to run programs in languages that are not supported by the browser
Can provide the client with data that does not reside on the client�s machine
Provides improved security measures since the script cannot be viewed by the browser

Lock prevents clients from modifying the variables stored in the Application object.
Unlock removes the lock from variables stored in the Application object.

Internet Explorer (supports VBScript, JavaScript)
Netscape Communicator/ Navigator (supports only JavaScript, VBScript can be also added too)

Including the RUNAT=SERVER attribute

Flush sends previous buffered output to the client immediately, but continues processing the script.
Clear erases any already-buffered HTML.
End causes the server to stop processing the script.

Expires specifies the number of minutes before a page cached on a browser expires.
ExpiresAbsolute sets the date and time at which a page cached on a browser expires.

Contents collection contains all the variables established for a session without using the tag.
Static collection contains all the objects created

- ASP executes code on the server side whereas the browser interprets HTML.
- ASP can use any scripting languages
- Gets feedback from the user and return information to the user
- Create pages that will be customized to display only things that will be of interest to a particular user
- Can edit contents of a web page by updating a text file or a database rather than the HTML code itself

Application_OnStart- This event will be fired when the first visitor hits the page.
Application_OnEnd- This event runs when the server is stopped.

Ad Rotator component- a way to manage advertisements on the web site.
Content Linker component - a technique to direct users through a set of pages on a web site by creating a list of URLs and description of the next and previous pages.
Browser Capabilities component - allows to customize the page to the ability of the browser viewing it.
Database Access component - allows to access data from the database.

tags provides space for the user to input values
the form has a button to submit information back to the server
It transfers control to another ASP page
It carries the information in the fields to another ASP page

-----tag: Provides input spaces (text boxes, combo boxes, radio button, etc.) on a form called fields. It has three attributes TYPE, NAME and VALUE. TYPE provides the characteristics of the field and the NAME specifies a name to the field by which it can be referred.

* Contents collection - contains all variables added via scripts in global.asa.
* Static collection - contains the names of all objects.

GET requests are string data that is visible to the end user via the URL and a limit of 2kb, POST requests have no limit on total data and the user can�t see the data in a query string.

This statement force the declaration of variables in VB before using them.

insert into tablename (fieldA, fieldB, fieldC)Values(�dataA�, �dataB�, �dataC�);

using colspan and rowspan

Use the sessions object

the ampersand symbol and ampersand space underscore across multiple lines

document.forms[�formName�].elements[�comboName�].options[i].value

A class allows you to define different style characteristics to the same HTML element.

SQL Injection, to prevent you probably need to use Stored Procedures instead of inline/incode SQL.

Variant.