There are three types of errors in programming: (a) Syntax Errors, (b) Runtime Errors, and (c) Logical Errors.

Syntax errors, also called as parsing errors, occur at the interpretation time for VBScript. For example, the following line causes a syntax error because it is missing a closing parenthesis.

Function ErrorHanlding_Demo()
dim x,y
x = "Tutorialspoint"
y = Ucase(x
End Function

Runtime errors, also called exceptions, occur during execution, after interpretation.
For example, the following line causes a runtime error because here the syntax is correct but at runtime it is trying to call fnmultiply, which is a non-existing function.

Function ErrorHanlding_Demo1()
Dim x,y
x = 10
y = 20
z = fnadd(x,y)
a = fnmultiply(x,y)
End Function

Function fnadd(x,y)
fnadd = x + y
End Function

Logical errors can be the most difficult type of errors to track down. These errors are not the result of a syntax or runtime error. Instead, they occur when you make a mistake in the logic that drives your script and you do not get the result you expected.
You cannot catch those errors, because it depends on your business requirement what type of logic you want to put in your program
. For example, dividing a number by zero or a script that is written which enters into infinite loop.