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VB Script
VB SCRIPT
Basic
Write text using VBScript
Format text with HTML tags
A function in the head section
A script in the body section
Variables
Create a variable
Insert a variable value in a text
Create an array
Procedures
Sub procedure
Function procedure
Conditional Statements
If...then..else statement
If...then..elseif statement
Select case statement
Random link
Looping
For..next loop
Looping through the HTML headers
For..each loop
Do...While loop
Date and Time Functions
Display date and time
Display the days
Display the months
Display the current month and day
Countdown to year 3000
Add a time interval to a date
Format date and time
Is this a date?
Other Built-in Functions
Uppercase or lowercase characters?
Remove leading or trailing spaces from a string
Reverse a string
Round a number
Return a random number
Return a random number between 0-99
Return a specified number of characters from the left or right side of a string
Replace some characters in a string
Return a specified number of characters from a string
And it produces this output:
To insert a script in an HTML document, use the <script> tag. Use the type attribute to define the scripting language.
Then comes the VBScript: The command for writing some text on a page is document.write:
The script ends:
Scripts in the head section: Scripts to be executed when they are called or when an event is triggered go in the head section. When you place a script in the head section you will assure that the script is loaded before anyone uses it:
Scripts in the body section: Scripts to be executed when the page loads go in the body section. When you place a script in the body section it generates the content of the page:
Scripts in both the body and the head section: You can place an unlimited number of scripts in your document, so you can have scripts in both the body and the head section.
Now you have created a variable. The name of the variable is "name".
You can also declare variables by using its name in your script. Like this:
Now you have also created a variable. The name of the variable is "name".
However, the last 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. This is because when you misspell for example the "name" variable to "nime" the script will automatically create a new variable called "nime". To prevent your script from doing this you can use the Option Explicit statement. When you use this statement you will have 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:
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 "name" has the value "Hege".
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.
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:
Similarly, the data can be retrieved from any element using the index of the particular array element you want. Like this:
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:
A Sub procedure:
A Function procedure:
Here you call a Function called "findname", the Function returns a value that will be stored in the variable "name".
Or, you can do like this:
Here you also call a Function called "findname", the Function returns a value that will be displayed in the message box.
When you call a Sub procedure you can use the Call statement, like this:
Or, you can omit the Call statement, like this:
In VBScript we have three conditional statements:
There is no ..else.. in this syntax. You just tell the code to perform one action if the 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":
There is no ..else.. in this syntax 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:
The first block of code will be executed if the condition is true, and the other block will be executed otherwise (if i is not equal to 10).
This is how it works: First we have a single expression (most often a variable), that is evaluated once. The value of the expression is then compared with the values for each Case in the structure. If there is a match, the block of code associated with that Case is executed.
In VBScript we have four looping statements:
You can use a counter variable that increases or decreases with each repetition of the loop, like this:
The For statement specifies the counter variable (i) and its start and end values. The Next statement increases the counter variable (i) by one.
In the example below, the counter variable (i) is increased by two each time the loop repeats.
To decrease the counter variable, you must use a negative Step value. You must specify an end value that is less than the start value.
In the example below, the counter variable (i) is decreased by two each time the loop repeats.
If i equals 9, the code inside the loop above will never be executed.
The code inside this loop will be executed at least one time, even if i is less than 10.
If i equals 10, the code inside the loop will never be executed.
The code inside this loop will be executed at least one time, even if i is equal to 10.
The code inside this loop will be executed as long as i is different from 10, and as long as i is greater than 10.
You have learned how to create variables and functions, and how to make different scripts run in response to different scenarios.
For more information on VBScript, please look at our VBScript examples and our VBScript references.
While scripts in an HTML file are executed on the client (in the browser), scripts in an ASP file are executed on the server.
With ASP you can dynamically edit, change or add any content of a Web page, respond to data submitted from HTML forms, access any data or databases and return the results to a browser, customize a Web page to make it more useful for individual users.
Since ASP files are returned as plain HTML, they can be viewed in any browser.
If you want to learn more about ASP, please visit our ASP tutorial.
his page contains all the built-in VBScript functions. The page is divided into following sections:
Basic
Write text using VBScript
Format text with HTML tags
A function in the head section
A script in the body section
Variables
Create a variable
Insert a variable value in a text
Create an array
Procedures
Sub procedure
Function procedure
Conditional Statements
If...then..else statement
If...then..elseif statement
Select case statement
Random link
Looping
For..next loop
Looping through the HTML headers
For..each loop
Do...While loop
Date and Time Functions
Display date and time
Display the days
Display the months
Display the current month and day
Countdown to year 3000
Add a time interval to a date
Format date and time
Is this a date?
Other Built-in Functions
Uppercase or lowercase characters?
Remove leading or trailing spaces from a string
Reverse a string
Round a number
Return a random number
Return a random number between 0-99
Return a specified number of characters from the left or right side of a string
Replace some characters in a string
Return a specified number of characters from a string
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
How Does it Work?
When a VBScript is inserted into a HTML document, the Internet browser will read the HTML and interpret the VBScript. The VBScript can be executed immediately, or at a later event.How to Put VBScript Code in an HTML Document
| <html><head></head><body><script type="text/vbscript">document.write("Hello from VBScript!")</script></body></html> |
And it produces this output:
| Hello from VBScript! |
To insert a script in an HTML document, use the <script> tag. Use the type attribute to define the scripting language.
| <script type="text/vbscript"> |
Then comes the VBScript: The command for writing some text on a page is document.write:
| document.write("Hello from VBScript!") |
The script ends:
| </script> |
How to Handle Older Browsers
Older browsers that do not support scripts will display the script as page content. To prevent them from doing this, you can use the HTML comment tag:| <script type="text/vbscript"><!-- some statements--></script> |
Where to Put the VBScript
Scripts 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, other times when a user triggers an event.Scripts in the head section: Scripts to be executed when they are called or when an event is triggered go in the head section. When you place a script in the head section you will assure that the script is loaded before anyone uses it:
| <html><head><script type="text/vbscript"> some statements</script></head> |
Scripts in the body section: Scripts to be executed when the page loads go in the body section. When you place a script in the body section it generates the content of the page:
| <html><head></head><body><script type="text/vbscript"> some statements</script></body> |
Scripts in both the body and the head section: You can place an unlimited number of scripts in your document, so you can have scripts in both the body and the head section.
| <html><head><script type="text/vbscript"> some statements</script></head><body><script type="text/vbscript"> some statements</script></body> |
What is a Variable?
A variable is a "container" for information you want to store. A variable's value can change during the script. You can refer to a variable by name to see its value or to change its value. In VBScript, all variables are of type variant, that can store different types of data.Rules for Variable Names:
- Must begin with a letter
- Cannot contain a period (.)
- Cannot exceed 255 characters
Declaring Variables
You can declare variables with the Dim, Public or the Private statement. Like this:| dim namename=some value |
Now you have created a variable. The name of the variable is "name".
You can also declare variables by using its name in your script. Like this:
| name=some value |
Now you have also created a variable. The name of the variable is "name".
However, the last 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. This is because when you misspell for example the "name" variable to "nime" the script will automatically create a new variable called "nime". To prevent your script from doing this you can use the Option Explicit statement. When you use this statement you will have 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 explicitdim namename=some value |
Assigning Values to Variables
You assign a value to a variable like this:| name="Hege"i=200 |
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 "name" has the value "Hege".
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.
Array Variables
Sometimes you want to assign more than one value to a single variable. Then you can create a variable that can contain a series of values. This is called an array variable. The declaration of an array variable uses parentheses ( ) following the variable name. 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) |
VBScript Procedures
We have two kinds of procedures: The Sub procedure and the Function procedure.A Sub procedure:
- is a series of statements, enclosed by the Sub and End Sub statements
- can perform actions, but does not return a value
- can take arguments that are passed to it by a calling procedure
- without arguments, must include an empty set of parentheses ()
| Sub mysub() some statementsEnd Sub or Sub mysub(argument1,argument2) some statementsEnd Sub |
A Function procedure:
- is a series of statements, enclosed by the Function and End Function statements
- can perform actions and can return a value
- can take arguments that are passed to it by a calling procedure
- without arguments, must include an empty set of parentheses ()
- returns a value by assigning a value to its name
| Function myfunction() some statementsmyfunction=some valueEnd Function orFunction myfunction(argument1,argument2) some statementsmyfunction=some valueEnd Function |
Call a Sub or Function Procedure
When you call a Function in your code, you do like this:| name = findname() |
Here you call a Function called "findname", the Function returns a value that will be stored in the variable "name".
Or, you can do like this:
| msgbox "Your name is " & findname() |
Here you also call a Function called "findname", the Function returns a value that will be displayed in the message box.
When you call a Sub procedure you can use the Call statement, like this:
| Call MyProc(argument) |
Or, you can omit the Call statement, like this:
| MyProc argument |
Conditional Statements
Very often when you write code, you want to perform different actions for different decisions. You can use conditional statements in your code to do this.In VBScript we have three conditional statements:
- if statement - use this statement if you want to execute a set of code when a condition is true
- if...then...else statement - use this statement if you want to select one of two sets of lines to execute
- if...then...elseif statement - use this statement if you want to select one of many sets of lines to execute
- select case statement - use this statement if you want to select one of many sets of lines to execute
If....Then.....Else
You should 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 i=10 Then msgbox "Hello" |
There is no ..else.. in this syntax. You just tell the code to perform one action if the 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 msgbox "Hello" i = i+1end If |
There is no ..else.. in this syntax 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:
| if i=10 then msgbox "Hello"else msgbox "Goodbye"end If |
The first block of code will be executed if the condition is true, and the other block will be executed otherwise (if i is not equal to 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:| if payment="Cash" then msgbox "You are going to pay cash!" elseif payment="Visa" then msgbox "You are going to pay with visa." elseif payment="AmEx" then msgbox "You are going to pay with American Express." else msgbox "Unknown method of payment."end If |
Select Case
You can also use the SELECT statement if you want to select one of many blocks of code to execute:| select case payment case "Cash" msgbox "You are going to pay cash" case "Visa" msgbox "You are going to pay with visa" case "AmEx" msgbox "You are going to pay with American Express" case Else msgbox "Unknown method of payment"end select |
This is how it works: First we have a single expression (most often a variable), that is evaluated once. The value of the expression is then compared with the values for each Case in the structure. If there is a match, the block of code associated with that Case is executed.
Looping Statements
Very often when you write code, you want to allow the same block of code to run a number of times. You can use looping statements in your code to do this.In VBScript we have four looping statements:
- For...Next statement - runs statements a specified number of times.
- For Each...Next statement - runs statements for each item in a collection or each element of an array
- Do...Loop statement - loops while or until a condition is true
- While...Wend statement - Do not use it - use the Do...Loop statement instead
For...Next Loop
You can use a For...Next statement to run a block of code, when you know how many repetitions you want.You can use a counter variable that increases or decreases with each repetition of the loop, like this:
| For i=1 to 10 some codeNext |
The For statement specifies the counter variable (i) and its start and end values. The Next statement increases the counter variable (i) by one.
Step Keyword
Using the Step keyword, you can increase or decrease the counter variable by the value you specify.In the example below, the counter variable (i) is increased by two each time the loop repeats.
| For i=2 To 10 Step 2 some codeNext |
To decrease the counter variable, you must use a negative Step value. You must specify an end value that is less than the start value.
In the example below, the counter variable (i) is decreased by two each time the loop repeats.
| For i=10 To 2 Step -2 some codeNext |
Exit a For...Next
You can exit a For...Next statement with the Exit For keyword.For Each...Next Loop
A For Each...Next loop repeats a block of code for each item in a collection, or for each element of an array.| dim cars(2)cars(0)="Volvo"cars(1)="Saab"cars(2)="BMW" For Each x in cars document.write(x & "<br />")Next |
Do...Loop
You can use Do...Loop statements to run a block of code when you do not know how many repetitions you want. The block of code is repeated while a condition is true or until a condition becomes true.Repeating Code While a Condition is True
You use the While keyword to check a condition in a Do...Loop statement.| Do While i>10 some codeLoop |
If i equals 9, the code inside the loop above will never be executed.
| Do some codeLoop While i>10 |
The code inside this loop will be executed at least one time, even if i is less than 10.
Repeating Code Until a Condition Becomes True
You use the Until keyword to check a condition in a Do...Loop statement.| Do Until i=10 some code Loop |
If i equals 10, the code inside the loop will never be executed.
| Do some codeLoop Until i=10 |
The code inside this loop will be executed at least one time, even if i is equal to 10.
Exit a Do...Loop
You can exit a Do...Loop statement with the Exit Do keyword.| Do Until i=10 i=i-1 If i<10 Then Exit DoLoop |
The code inside this loop will be executed as long as i is different from 10, and as long as i is greater than 10.
VBScript Summary
This tutorial has taught you how to add VBScript to your HTML pages, to make your web site more dynamic and interactive.You have learned how to create variables and functions, and how to make different scripts run in response to different scenarios.
For more information on VBScript, please look at our VBScript examples and our VBScript references.
Now You Know VBScript, What's Next?
The next step is to learn ASP.While scripts in an HTML file are executed on the client (in the browser), scripts in an ASP file are executed on the server.
With ASP you can dynamically edit, change or add any content of a Web page, respond to data submitted from HTML forms, access any data or databases and return the results to a browser, customize a Web page to make it more useful for individual users.
Since ASP files are returned as plain HTML, they can be viewed in any browser.
If you want to learn more about ASP, please visit our ASP tutorial.
his page contains all the built-in VBScript functions. The page is divided into following sections:
| | | |
Date/Time Functions
| Function | Description |
| CDate | Converts a valid date and time expression to the variant of subtype Date |
| Date | Returns the current system date |
| DateAdd | Returns a date to which a specified time interval has been added |
| DateDiff | Returns the number of intervals between two dates |
| DatePart | Returns the specified part of a given date |
| DateSerial | Returns the date for a specified year, month, and day |
| DateValue | Returns a date |
| Day | Returns a number that represents the day of the month (between 1 and 31, inclusive) |
| FormatDateTime | Returns an expression formatted as a date or time |
| Hour | Returns a number that represents the hour of the day (between 0 and 23, inclusive) |
| IsDate | Returns a Boolean value that indicates if the evaluated expression can be converted to a date |
| Minute | Returns a number that represents the minute of the hour (between 0 and 59, inclusive) |
| Month | Returns a number that represents the month of the year (between 1 and 12, inclusive) |
| MonthName | Returns the name of a specified month |
| Now | Returns the current system date and time |
| Second | Returns a number that represents the second of the minute (between 0 and 59, inclusive) |
| Time | Returns the current system time |
| Timer | Returns the number of seconds since 12:00 AM |
| TimeSerial | Returns the time for a specific hour, minute, and second |
| TimeValue | Returns a time |
| Weekday | Returns a number that represents the day of the week (between 1 and 7, inclusive) |
| WeekdayName | Returns the weekday name of a specified day of the week |
| Year | Returns a number that represents the year |
Conversion Functions | Top |
| Function | Description |
| Asc | Converts the first letter in a string to ANSI code |
| CBool | Converts an expression to a variant of subtype Boolean |
| CByte | Converts an expression to a variant of subtype Byte |
| CCur | Converts an expression to a variant of subtype Currency |
| CDate | Converts a valid date and time expression to the variant of subtype Date |
| CDbl | Converts an expression to a variant of subtype Double |
| Chr | Converts the specified ANSI code to a character |
| CInt | Converts an expression to a variant of subtype Integer |
| CLng | Converts an expression to a variant of subtype Long |
| CSng | Converts an expression to a variant of subtype Single |
| CStr | Converts an expression to a variant of subtype String |
| Hex | Returns the hexadecimal value of a specified number |
| Oct | Returns the octal value of a specified number |
Format Functions | Top |
| Function | Description |
| FormatCurrency | Returns an expression formatted as a currency value |
| FormatDateTime | Returns an expression formatted as a date or time |
| FormatNumber | Returns an expression formatted as a number |
| FormatPercent | Returns an expression formatted as a percentage |
Math Functions | Top |
| Function | Description |
| Abs | Returns the absolute value of a specified number |
| Atn | Returns the arctangent of a specified number |
| Cos | Returns the cosine of a specified number (angle) |
| Exp | Returns e raised to a power |
| Hex | Returns the hexadecimal value of a specified number |
| Int | Returns the integer part of a specified number |
| Fix | Returns the integer part of a specified number |
| Log | Returns the natural logarithm of a specified number |
| Oct | Returns the octal value of a specified number |
| Rnd | Returns a random number less than 1 but greater or equal to 0 |
| Sgn | Returns an integer that indicates the sign of a specified number |
| Sin | Returns the sine of a specified number (angle) |
| Sqr | Returns the square root of a specified number |
| Tan | Returns the tangent of a specified number (angle) |
Array Functions | Top |
| Function | Description |
| Array | Returns a variant containing an array |
| Filter | Returns a zero-based array that contains a subset of a string array based on a filter criteria |
| IsArray | Returns a Boolean value that indicates whether a specified variable is an array |
| Join | Returns a string that consists of a number of substrings in an array |
| LBound | Returns the smallest subscript for the indicated dimension of an array |
| Split | Returns a zero-based, one-dimensional array that contains a specified number of substrings |
| UBound | Returns the largest subscript for the indicated dimension of an array |
String Functions | Top |
| Function | Description |
| InStr | Returns the position of the first occurrence of one string within another. The search begins at the first character of the string |
| InStrRev | Returns the position of the first occurrence of one string within another. The search begins at the last character of the string |
| LCase | Converts a specified string to lowercase |
| Left | Returns a specified number of characters from the left side of a string |
| Len | Returns the number of characters in a string |
| LTrim | Removes spaces on the left side of a string |
| RTrim | Removes spaces on the right side of a string |
| Trim | Removes spaces on both the left and the right side of a string |
| Mid | Returns a specified number of characters from a string |
| Replace | Replaces a specified part of a string with another string a specified number of times |
| Right | Returns a specified number of characters from the right side of a string |
| Space | Returns a string that consists of a specified number of spaces |
| StrComp | Compares two strings and returns a value that represents the result of the comparison |
| String | Returns a string that contains a repeating character of a specified length |
| StrReverse | Reverses a string |
| UCase | Converts a specified string to uppercase |
Other Functions | Top |
| Function | Description |
| CreateObject | Creates an object of a specified type |
| Eval | Evaluates an expression and returns the result |
| GetLocale | Returns the current locale ID |
| GetObject | Returns a reference to an automation object from a file |
| GetRef | Allows you to connect a VBScript procedure to a DHTML event on your pages |
| InputBox | Displays a dialog box, where the user can write some input and/or click on a button, and returns the contents |
| IsEmpty | Returns a Boolean value that indicates whether a specified variable has been initialized or not |
| IsNull | Returns a Boolean value that indicates whether a specified expression contains no valid data (Null) |
| IsNumeric | Returns a Boolean value that indicates whether a specified expression can be evaluated as a number |
| IsObject | Returns a Boolean value that indicates whether the specified expression is an automation object |
| LoadPicture | Returns a picture object. Available only on 32-bit platforms |
| MsgBox | Displays a message box, waits for the user to click a button, and returns a value that indicates which button the user clicked |
| RGB | Returns a number that represents an RGB color value |
| Round | Rounds a number |
| ScriptEngine | Returns the scripting language in use |
| ScriptEngineBuildVersion | Returns the build version number of the scripting engine in use |
| ScriptEngineMajorVersion | Returns the major version number of the scripting engine in use |
| ScriptEngineMinorVersion | Returns the minor version number of the scripting engine in use |
| SetLocale | Sets the locale ID and returns the previous locale ID |
| TypeName | Returns the subtype of a specified variable |
| VarType | Returns a value that indicates the subtype of a specified variable |
VBScript Keywords
| Keyword | Description |
| empty | Used to indicate an uninitialized variable value. A variable value is uninitialized when it is first created and no value is assigned to it, or when a variable value is explicitly set to empty. Example: dim x 'the variable x is uninitialized! x="ff" 'the variable x is NOT uninitialized anymore x=empty 'the variable x is uninitialized! Note: This is not the same as Null!! |
| isEmpty | Used to test if a variable is uninitialized. Example: If (isEmpty(x)) 'is x uninitialized? |
| nothing | Used to indicate an uninitialized object value, or to disassociate an object variable from an object to release system resources. Example: set myObject=nothing |
| is nothing | Used to test if a value is an initialized object. Example: If (myObject Is Nothing) 'is it unset? Note: If you compare a value to Nothing, you will not get the right result! Example: If (myObject = Nothing) 'always false! |
| null | Used to indicate that a variable contains no valid data. One way to think of Null is that someone has explicitly set the value to "invalid", unlike Empty where the value is "not set". Note: This is not the same as Empty or Nothing!! Example: x=Null 'x contains no valid data |
| isNull | Used to test if a value contains invalid data. Example: if (isNull(x)) 'is x invalid? |
| true | Used to indicate a Boolean condition that is correct (true has a value of -1) |
| false | Used to indicate a Boolean condition that is not correct (false has a value of 0) |
|
arunraj |
Latest page update: made by arunraj
, Mar 16 2007, 4:51 AM EDT
(about this update
About This Update
Edited by arunraj
3960 words added view changes - complete history) |
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