VBScript

VBScript is a Microsoft scripting language.

VBScript is the default scripting language in ASP.

Client-side VBScript only works in Internet Explorer!!!

VBScript Editor

With our online editor, you can edit the VBScript code, and click on a button to view the result.

Example (IE Only)

<html>
<body>

<script type="text/vbscript">
document.write("This is my first VBScript!")
</script>

</body>
</html>

What is VBScript?

VBScript is a scripting language
A scripting language is a lightweight programming language
VBScript is a light version of Microsoft's programming language Visual Basic
VBScript is only supported by Microsoft's browsers (Internet Explorer)

How Does it Work?

When a VBScript is inserted into an HTML document, Internet Explorer browser will read the HTML and interpret the VBScript. The VBScript can be executed immediately, or at a later event.
VBScript only works in Microsoft browsers (Internet Explorer).

VBScript Where To...

VBScripts can be placed in the body and in the head section of an HTML document.

Where to Put the VBScript

VBScripts in a page will be executed immediately while the page loads into the browser. This is not always what we want. Sometimes we want to execute a script when a page loads, or at a later event, such as when a user clicks a button. When this is the case we put the script inside a function or a sub procedure, you will learn about procedures in a later chapter.

Scripts in <head>

Put your functions and sub procedures in the head section, this way they are all in one place, and they do not interfere with page content.

Example (IE Only)

<html>
<head>
<script type="text/vbscript">
function myFunction()
alert("Hello World!")
end function
</script>
</head>

<body onload="myFunction()">
</body>
</html>

Scripts in <body>

If you don't want your script to be placed inside a function, and especially if your script should write page content, it should be placed in the body section.

Example (IE Only)

<html>
<head>
</head>

<body>
<script type="text/vbscript">
document.write("This message is written by VBScript")
</script>
</body>

</html>

Scripts in <head> and <body>

You can place an unlimited number of scripts in your document, and you can have scripts in both the body and the head section.

Example (IE Only)

<html>
<head>
<script type="text/vbscript">
function myFunction()
alert("Hello World!")
end function
</script>
</head>

<body>
<button onclick="myFunction()">Click me</button>
<script type="text/vbscript">
document.write("This message is written by VBScript")
</script>
</body>
</html>

VBScript Variables

As with algebra, VBScript variables are used to hold values or expressions.

A variable can have a short name, like x, or a more descriptive name, like carname.

Rules for VBScript variable names:

Must begin with a letter
Cannot contain a period (.)
Cannot exceed 255 characters

In VBScript, all variables are of type variant, that can store different types of data.

Declaring (Creating) VBScript Variables

Creating variables in VBScript is most often referred to as "declaring" variables.

You can declare VBScript variables with the Dim, Public or the Private statement. Like this:

Dim x
Dim carname

Now you have created two variables. The name of the variables are "x" and "carname".

You can also declare variables by using its name in a script. Like this:

carname="Volvo"

Now you have also created a variable. The name of the variable is "carname". However, this method is not a good practice, because you can misspell the variable name later in your script, and that can cause strange results when your script is running.

If you misspell for example the "carname" variable to "carnime", the script will automatically create a new variable called "carnime". To prevent your script from doing this, you can use the Option Explicit statement. This statement forces you to declare all your variables with the dim, public or private statement.

Put the Option Explicit statement on the top of your script. Like this:

Option Explicit
Dim carname
carname=some value

Assigning Values to Variables

You assign a value to a variable like this:

carname="Volvo"
x=10

The variable name is on the left side of the expression and the value you want to assign to the variable is on the right. Now the variable "carname" has the value of "Volvo", and the variable "x" has the value of "10".

Lifetime of Variables

How long a variable exists is its lifetime.

When you declare a variable within a procedure, the variable can only be accessed within that procedure. When the procedure exits, the variable is destroyed. These variables are called local variables. You can have local variables with the same name in different procedures, because each is recognized only by the procedure in which it is declared.

If you declare a variable outside a procedure, all the procedures on your page can access it. The lifetime of these variables starts when they are declared, and ends when the page is closed.

VBScript Array Variables

An array variable is used to store multiple values in a single variable.

In the following example, an array containing 3 elements is declared:

Dim names(2)

The number shown in the parentheses is 2. We start at zero so this array contains 3 elements. This is a fixed-size array. You assign data to each of the elements of the array like this:

names(0)="Tove"
names(1)="Jani"
names(2)="Stale"

Similarly, the data can be retrieved from any element using the index of the particular array element you want. Like this:

mother=names(0)

You can have up to 60 dimensions in an array. Multiple dimensions are declared by separating the numbers in the parentheses with commas. Here we have a two-dimensional array consisting of 5 rows and 7 columns:

Dim table(4,6)

Asign data to a two-dimensional array:

Example (IE Only)

<html>
<body>

<script type="text/vbscript">
Dim x(2,2)
x(0,0)="Volvo"
x(0,1)="BMW"
x(0,2)="Ford"
x(1,0)="Apple"
x(1,1)="Orange"
x(1,2)="Banana"
x(2,0)="Coke"
x(2,1)="Pepsi"
x(2,2)="Sprite"
for i=0 to 2
    document.write("<p>")
    for j=0 to 2
        document.write(x(i,j) & "<br />")
    next
    document.write("</p>")
next
</script>

</body>
</html>

VBScript Conditional Statements

Conditional Statements

Conditional statements are used to perform different actions for different decisions.
In VBScript we have four conditional statements:

If statement - executes a set of code when a condition is true
If...Then...Else statement - select one of two sets of lines to execute
If...Then...ElseIf statement - select one of many sets of lines to execute
Select Case statement - select one of many sets of lines to execute

If...Then...Else

Use the If...Then...Else statement if you want to

execute some code if a condition is true
select one of two blocks of code to execute

If you want to execute only one statement when a condition is true, you can write the code on one line:

If i=10 Then alert("Hello")

There is no ..Else.. in this syntax. You just tell the code to perform one action if a condition is true (in this case If i=10).
If you want to execute more than one statement when a condition is true, you must put each statement on separate lines, and end the statement with the keyword "End If":

If i=10 Then
alert("Hello")
i = i+1
End If

There is no ..Else.. in the example above either. You just tell the code to perform multiple actions if the condition is true.
If you want to execute a statement if a condition is true and execute another statement if the condition is not true, you must add the "Else" keyword:

Example (IE Only)

<html>
<body>
</head>
<script type="text/vbscript">
Function greeting()
i=hour(time)
If i < 10 Then
document.write("Good morning!")
Else
document.write("Have a nice day!")
End If
End Function
</script>
</head>

<body onload="greeting()">
</body>

</html>

In the example above, the first block of code will be executed if the condition is true, and the other block will be executed otherwise (if i is greater than 10).

If...Then...ElseIf

You can use the If...Then...ElseIf statement if you want to select one of many blocks of code to execute:

Example (IE Only)

<html>
<body>
</head>
<script type="text/vbscript">
Function greeting()
i=hour(time)
If i = 10 Then
document.write("Just started...!")
ElseIf i = 11 then
document.write("Hungry!")
ElseIf i = 12 then
document.write("Ah, lunch-time!")
ElseIf i = 16 then
document.write("Time to go home!")
Else
document.write("Unknown")
End If
End Function
</script>
</head>

<body onload="greeting()">
</body>

</html>

CS(engineering)

Pages

VBScript

What is VBScript?

How Does it Work?

VBScript Where To...

Where to Put the VBScript

Scripts in <head>

Example (IE Only)

Scripts in <body>

Example (IE Only)

Scripts in <head> and <body>

Example (IE Only)

VBScript Conditional Statements

Conditional Statements

If...Then...Else

Example (IE Only)

If...Then...ElseIf

Example (IE Only)