VBScript Tutorial
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Example
- If...then..else statements
- This example demonstrates how to write if...then..else statements.
- If...then..elseif statements
- This example demonstrates how to write if...then...elseif... statements.
- Select case statement
- This example demonstrates how to write a select case statement.
Conditional statements
Frequently, when we write code, we need to perform different operations based on different judgments. We can use conditional statements to accomplish this work.
In VBScript, we can use three conditional statements:
- if statement
- If you want to execute a series of codes when the condition is true, you can use this statement.
- if...then...else statement
- If you want to execute one of two code sets, you can use this statement.
- if...then...elseif statement
- If you want to select one of multiple code sets to execute, you can use this statement.
- select case statement
- If you want to select one of multiple code sets to execute, you can use this statement.
If....Then.....Else
In the following situations, you can use the If...Then...Else statement:
- Execute a block of code when the condition is true
- Select one of the two code blocks to execute
If you need to execute only one line of code when the condition is true, you can write the code on one line:
if i=10 Then msgbox "Hello"
In the above code, there is no .else.. statement. We simply made the code execute one operation when the condition is true (when i is 10).
If we need to execute more than one statement when the condition is true, we must write one statement per line and then use the keyword "End If" to end this statement:
if i=10 Then msgbox "Hello" i = i+1 end If
In the above code, there is no .else.. statement. We simply made the code execute multiple operations when the condition is true.
If we want to execute a statement when the condition is true and another statement when the condition is not true, we must add the keyword "Else":
if i=10 then msgbox "Hello" else msgbox "Goodbye" end If
The first block of code will be executed when the condition is true, and the second block of code will be executed when the condition is not met (when i is not equal to 10).
If....Then.....Elseif
If you want to select one of multiple code sets to execute, you can use the if...then...elseif statements:
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
If you want to select one of multiple sets of code to execute, you can use the SELECT statement:
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
The working principle of the above code: First, we need a simple expression (often a variable), and this expression will be evaluated once. Then, the value of the expression will be compared with the value in each case, and if a match is found, the code corresponding to the matched case will be executed.
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