Eval Function

Description

Evaluates an expression and returns the result.

Syntax

[result = ]Eval(expression)

The Eval function syntax has these parts:

Part	Description
result	Optional. Variable to which return value assignment is made. If result is not specified, consider using the Execute statement instead.
expression	Required. String containing any legal VBScript expression.

Remarks

In VBScript, x = y can be interpreted two ways. The first is as an assignment statement, where the value of y is assigned to x. The second interpretation is as an expression that tests if x and y have the same value. If they do, result is True; if they are not, result is False. The Eval method always uses the second interpretation, whereas the Execute statement always uses the first.

Note  In Microsoft® JScript™, no confusion exists between assignment and comparison, because the assignment operator (=) is different from the comparison operator (==).

The following example illustrates the use of the Eval function:

Sub GuessANumber
  Dim Guess, RndNum
  RndNum = Int((100) * Rnd(1) + 1)
  Guess = CInt(InputBox("Enter your guess:",,0))
  Do
    If Eval("Guess = RndNum") Then
      MsgBox "Congratulations! You guessed it!"
      Exit Sub
    Else
      Guess = CInt(InputBox("Sorry! Try again.",,0))
    End If
  Loop Until Guess = 0
End Sub