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)



Function greeting()
i=hour(time)
If i < 10 Then
document.write("Good morning!")
Else
document.write("Have a nice day!")
End If
End Function








Try it yourself »

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)



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








Try it yourself »

Select Case

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



d=weekday(date)
Select Case d
Case 1
document.write("Sleepy Sunday")
Case 2
document.write("Monday again!")
Case 3
document.write("Just Tuesday!")
Case 4
document.write("Wednesday!")
Case 5
document.write("Thursday...")
Case 6
document.write("Finally Friday!")
Case else
document.write("Super Saturday!!!!")
End Select





Try it yourself »

This is how it works: First we have a single expres​sion(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.