VBScript Interview Preparation Guide

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VB script is a Microsoft programming language and it resembles a lower version of the VB. It is an Active Scripting language. This scripting language is included in windows operating system by default. With the use of msscript.ocx you can install VB Script.

A simple example detailing the running of VB Script is by utilizing Windows Script host environment. Visual basic is a stand alone application which has a .vbs as extension. Input can be provided through graphical user interface and output can be obtained by Wscript.exe from dialog and input boxes. From command line it can be invoked by Cscript.exe.

This is a scripting language developed by Microsoft and is based loosely on Visual Basic. Its functionality in a web environment is defendant upon either an ASP engine or the Windows Scripting Host, and must be used on a Windows hosting platform.

Asc() - Returns ANSI Character Code
Chr() - Returns Character from ANSI Code
InStr() - Find a string within another
InStrRev() - Find a string within another (Reverse)
LCase() - Convert a string to lowercase
Left() - Crops a string from left
Len() - Determine the length of a string
LTrim() - Remove leading spaces from a string
Mid() - Crops a string
Replace() - Replace a substring within a string
Right() - Crops a string from right
RTrim() - Remove trailing spaces from a string
Space() - Creates a string with the specified number of spaces
StrComp() - Compare two strings
String() - Creates a repeated character string
StrReverse() - Reverse the characters of a string
Trim() - Remove both leading and trailing spaces from a string
UCase() - Convert a string to uppercase

Date(),
Time(),
Now(),
Left(),
Right(),
Mid()

The actions that are performed by clicking, pressing keys, moving mouse, dragging and dropping etc are called as events. Event handling is the way to capture these events and perform the actions accordingly.

.wsf files are modeled in similar to XML. They can be executed with the help of Wscript.exe and it can be done from the command line also. This .wsf file can have multiple visual basic files. Reuse functionality is present with this extension file.

.hta extension is used whenever you want to include a VB script in HTML. Here HTML acts as an interface and VB Script as the programming language. .hta extension files do run in the safe and trusted zone of Internet explorer. Although they run in the trusted zone querying is restricted as it has to pass the guidelines of internet explorer.

If functionality aspect is considered VB Script acts similar to Java Script but it is compatible only on internet explorer. They interact with Document object model. Visual basic script can also be used for server side processing with ASP.

VB and JavaScript are much similar in functionality. They both interact with the document object model of the page. Many browsers have compatibility with Java Script but they are not compatible with VB script as such. For client side scripting developers using VB Script should always make sure of cross browser compatibility which is not the case when working with VBScript.

Visual Basic should rely on ASP for sever side processing. Asp.dll is used to make VB Script run on ASP engine and it invokes vbscript.dll. VB Script should be embedded within <% and %> context switches. ASP can provide varied functionality to VB Script.

Active X technology can be used to give much more functionality to VB Script. VB provides sub routines, functions, string manipulation, data/time, error handling, etc. VB can have more functionality added to it by working with languages such as ASP.

Scripting Runtime library is very important for the functioning of Visual basic script because it gives much more functionality such as File management, text operations and file modification features. Scrrun.dll is used very much in programming VB.

ADODB.Stream class can be used as string builder. VBScript string concatenation can be very costly because of frequent memory allocation features. Binary file and memory I/O operation is provided by ADODB.Stream class. This is widely used to convert bytes into string, etc.

Arrays in VB Script should be assigned within the variant separated by a comma. If arguments are not specified then the string is regarded as empty. After specifying the elements in an array an index number should be used indicating the desired element.

According to the first letter in a string it returns the ANSI code relevant to that first letter. If string is not present then a runtime error occurs. Asc function returns the first byte used. It is used only with elements containing byte data in a string.

Filter expression returns an array based on a specific filter search condition and it returns a zero based array. Arguments included in the filter array are Input strings, value, include and compare. If there is no match for the value it returns an empty string.

There are many useful constants present in Visual basic script which you can use in your code. They ease your work load by remembering value and implementing in the code. Maintenance is easy with VB Script because it can easily change the feature of constants.

Tristate constants can be used with functions which allow formatting of numbers. These constants can be used with VB Script without defining them. It can be used anywhere in the code to reflect and represent the values.

In operator precedence expressions are evaluated and resolved in a predetermined order. The order of evaluation can be modulated if you use parenthesis. Expressions present in parenthesis are evaluated first.

Order of evaluation of operators is, first arithmetic operators are evaluated, and comparison operators are evaluated next and at the last logical operators are evaluated at the last. In arithmetic operators negation, Exponentiation, multiplication and division, integer division, modulus arithmetic, addition and subtraction and string concatenation are provided.