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Published on: Friday 18th September 1998 By: Lawrence Elliot
VBScript is a subset of the Visual Basic Programming language. The result of the slimming down process is a very small language that is easy to use. You may be interest to know that there is also available Visual Basic for Applications (VBA) for use with Microsoft Word, Excel, Access etc.
JavaScript can do all that VBScript can do and far more. So why use VBScript instead of JavaScript? Because VBScript is much easier to learn than JavaScript.
For instance, here is the VBScript code to request the users name and display it in a message box on your web page and print your name in large letters:
<HTML>
<HEAD>
<TITLE> "VBScript Demo"</TITLE>
<SCRIPT LANGUAGE="VBScript">
<!--
' Your Script goes here.
YourName = InputBox("What is your name?")
MsgBox "YourName"
' or you can display YourName like this:
Document.Write" <H1>"
Document.Write YourName
Document.Write" <\/H1>"
- ->
</SCRIPT>
</HEAD>
</BODY>
</HTML>There is one big drawback to using VBScript and that is that it isn't supported by non-Internet Explorer browsers.
Much of the power of VBScript comes from its ability to control the thousands of ActiveX controls that are available. It is a fairly straight forward exercise to create your own ActiveX controls using ActiveX Control Pad which is free from Microsoft. For the people who still use Notepad to write their HTML files, you really need to use Control Pad. For instance, you may call a text box a "text box" but to every machine in the world its name is really: 8BD21D10-EC42-11CE-9E0D-00AA006002F3
The reason behind this great long number is that if the person displaying your web page speaks a different language, the persons computer displays everything in the other language. Don't be put off by the long CLASSID number, you don't have to remember it or even type it in, Control Pad does it all for you.
| VBScript | JavaScript | |
| Arrays |
Declaration (e.g., Dim, Static) Lbound, Ubound ReDim, Erase |
new Array() new Object() |
| Assignment |
= |
= |
| Comments |
REM Single Quote (') |
// /* comment */ |
| Control Flow |
Do ....Loop For ...Next, For Each ...Next While ...Wend If ... Then ...Else |
do {
statements
} while (condition)
for (expression; condition; [expression]) {
statements
}
for (variable in object) {
statements
}
while (condition) {
statements
}
if (condition) {
statements1
}
else {
statements2
}
switch (expression){
case label :
statement;
break;
case label :
statement;
break;
...
default : statement;
}
|
| Error Trapping |
On Error Err Object |
window.onError = handler-func window.onError(message,url,line) |
| Literals |
Empty Nothing Null True, False User Defined Literals(e.g., 123.456, "test") |
NaN null true, false User Defined Literals(e.g., 123.456, "test") |
| Operators |
Arithmetic +, -, *, /, \, ^, Mod, Negation ( -) Strings concatenation (&) Comparison =, <, >, <>, <=, >=, Is Logical Not, And, Or, Xor, Eqv, Imp |
Arithmetic +, ++, -, --, *, / % String + += Logical && || ! Bitwise & ^ | ~ << >> >>> Assignment = += -= *= /= %= &= ^= |= <<= >>= >>>= Comparison == |= > >= < <= Special ?: , delete new this typeof void |
| Options |
Option Explicit |
N/A |
| Declaring Procedures |
Functions Sub |
function function-name(arg1, arg2, ... argN) |
| Calling Procedures: |
Call |
function function-name(arg1, arg2, ... argN) { statements; } |
| Exiting Procedures |
Exit Function Exit Sub |
|
| Parameters for Procedures |
ByVal, ByRef |
|
| Procedure-level Variables |
Dim Static |
var variable-name |
| Module level Variables |
Private dim |
var variable-name |
When one uses Option Explicit it forces the user to declare all variables. If one tries to use a variable without declaring it an error is generated. If one doesn't use Option Explicit one is free to use variables without declaring them, however, this is bad programming practice as it is easy to misspell a variable and produce faulty code.
| VBScript | JavaScript | |
| Divide & return an integer value | \ | N/A |
|---|---|---|
| Exponentiation | ^ | N/A |
| Modulas | MOD | % |
| String Concatenation | + or & | + |
| Left Shift | N/A | << |
| Right Shift | N/A | >> |
| Bitwise AND | AND | & |
| Bitwise OR | OR | | |
| Bitwise XOR | XOR | ^ |
| Bitwise complement | NOT | ~ |
| Not equal to | <> | != |
| Evaluation AND | AND | && |
| Evaluation OR | OR | || |
| Evaluation XOR | XOR | N/A |
A Function is a way of dividing up a program into reusable chunks. A Function is usually passed a list of variables, performs action upon these variables and returns a value.
Function Name(arguments)
code body of function
End FunctionSimilarly Subs in VBScript:
Sub
code body of function
End subTrim, Ltrim, Rtrim:
MyString = " This is a Test " NewString = Trim(MyString) ' NewString = "This is a Test" NewString = Ltrim(MyString) ' NewString = "This is a test " NewString = Rtrim(MyString) ' NewString = " This is a test"
Len:
MyString = "Test this string" l = Len(MyString) ' l = 16
Mid:
NewString = Mid(MyString,1,1) ' NewString = "T" NewString = Mid(MyString,6,4) ' NewString = "this"
Left:
MyString = "Test this string" NewString = Left(MyString,3) ' NewString = "Tes"
Right:
MyString = "Test this string" NewString = Right(MyString,4) ' NewString = "ring"
For example to count the number of spaces in MyString:
<HTML> <HEAD> <TITLE> "VBScript Demo"</TITLE> <SCRIPT LANGUAGE="VBScript"> <!-- Dim MyString, SpaceCount, Length, Position MyString = "This is my test string" SpaceCount = 0 Length = Len(MyString) For Position = 1 to Length If Mid(MyString, Position, 1) = Chr(32) Then ' Chr(32) equals the space character. SpaceCount = SpaceCount + 1 End If Next MsgBox SpaceCount 'SpaceCount would equal 4 --> </SCRIPT> </HEAD> </BODY> </HTML>
InStr and InStrRev. Syntax is: Instr([start,] OriginalString, SubString{, Compare])
Start defines the start of the search and is optional, Compare lets you defining whether the search should be case sensitive and is also optional.
MyString = "This is a test" Position = InStr(MyString, "s") ' Position = 4 Position = InStrRev(MyString, "s") ' Position = 13 Position = InStr(5, MyString, "s") ' Position = 7
A one-dimensional array is a way to group items so that you can refer to each item individually by means of its Index:
Dim MyButton(4)
This means that you have five elements in an array, MyButton(0) to MyButton(4).
Dim MyButtons()
NumberOfButtons = InputBox("How many Buttons")
ReDim MyButtons(NumberOfButtons)
Format
MsgBox FormatDatTime(Now, vbGeneralDate) ' 15/6/98 5:15:20 PM
vbLongDate Monday, June 15, 1998
vbShortDate 15/6/98
vbLongTime 5:15;20 PM
vbShortTime 17:15 (24-hour clock) Much of the power of VBScript comes from its ability to control the thousands of ActiveX controls that are available.
ActiveX Control Pad available free from Microsoft combines a simple HTML editor with some very powerful features for working with ActiveX Controls. The key is that ActiveX Control Pad will let you do the following: Specify the type of ActiveX control, such as command button or text box that you want to insert.
ActiveX Control Pad comes with a tool named Script Wizard. Script Wizard will generate code automatically when you give it directions, however, it only generates the code for the controls used. If you need additional operability you will have to add the code by hand.
Visual Basic 5 Control Creation Edition is another way in which you can create your own ActiveX controls and again it is available from Microsoft and again its free. VB5CCE can create full blown ActiveX controls as 32-bit OCX's.
VBScript is the name given to Microsoft's Visual Basic Scripting Edition. It is a subset of the Visual Basic for Applications (VBA) language although it has a few features that haven't yet been introduced into VBA. It can also be use to program Windows95 and Windows NT by using the Microsoft Windows Scripting Host.
VBScript is part of Internet Explorer version 4 or later for the Windows platform. This means that millions of people have VBScript and don't even know it!
Have a look at VBScript at Microsoft. This site has a list of non-Microsoft sites that you might find useful. It also contains information about VBScript news groups.
JavaScript is a language designed by Netscape Communications for programming Web pages. Thus VBScript and JavaScript are designed to do the same job. In my opinion JavaScript has a much steeper learning curve than VBScript since JavaScript uses syntax similar to the cryptic C programming language.
There are several books on the subject of VBScript available. Have a look at http://computer-manuals.co.uk. I can recommend "Learning Visual Basic Scripting Edition Now" from Microsoft Press ISBN 1-57231-347-1.
Browser Redirection using VBScript
Rattling Keys and Chasing Mice With VBScript