Difference between ByRef and ByVal

ByRef and ByVal are two ways to pass arguments to a function or subroutine in VBScript. Understanding the difference between two is simple.

Let us start with ByVal. Suppose a function or subroutine has an argument which accepts a variable with byval,suppose a variable x is passed as argument to the function, The value of variable does not change once the function is executed successfully.

Now let us move to ByRef. ByRef means passing value as a reference. Suppose a function or subroutine has an argument which accepts a variable with byref, suppose variable x is passed as argument to the function, The value of variable changes once the function is executed successfully.

Writing the below function in a notepad and running as a vbscript will help to differentiate ByVal and ByRef

By Ref Code:

Dim x

x= 5

call squareofNumber(x)

msgbox x

Function squareofNumber(ByRef varx)

        varx = varx*varx

        msgbox varx

End function

ByVal Code:

Dim x

x= 5

call squareofNumber(x)

msgbox x

Function squareofNumber(Byval varx)

        varx = varx*varx

        msgbox varx

End function

 By default, if we do not provide ByVal or Byref, it takes the argument as ByRef.