ASP VB Conditionals
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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 response.write("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
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

i=hour(time)
If i < 10 Then
response.write("Good morning!")
Else
response.write("Have a nice day!")
End If
Show Example »

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

i=hour(time)
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
Show Example »

Select Case

You can also use the "Select Case" statement if you want to select one of many blocks of code to execute:

Example

d=weekday(date)
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
Show Example »

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.