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:
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":
response.write("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
If i < 10 Then
response.write("Good morning!")
Else
response.write("Have a nice day!")
End If
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
If i = 10 Then
response.write("Just started...!")
ElseIf i = 11 Then
response.write("Hungry!")
ElseIf i = 12 Then
response.write("Ah, lunch-time!")
ElseIf i = 16 Then
response.write("Time to go home!")
Else
response.write("Unknown")
End If
Select Case
You can also use the "Select Case" statement if you want to select one of many blocks of code to execute:
Example
Select Case d
Case 1
response.write("Sleepy Sunday")
Case 2
response.write("Monday again!")
Case 3
response.write("Just Tuesday!")
Case 4
response.write("Wednesday!")
Case 5
response.write("Thursday...")
Case 6
response.write("Finally Friday!")
Case else
response.write("Super Saturday!!!!")
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.