Visual Basic

Public Class Form1
    Dim Pass As String
    Dim User As String
    Dim Account As userlist
    Structure userlist
        Dim registeruser As String
        Dim registerpass As String
    End Structure

    Private Sub Register_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Register.Click
        Account.registeruser = signuser.Text
        Account.registerpass = signpass.Text
        signuser.Clear()
        signpass.Clear()
    End Sub
    Private Sub Submit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Submit.Click
        User = username.Text
        Pass = pword.Text

        If Pass = Account.registerpass And User = Account.registeruser Then
            Label7.Text = "Welcome"
        Else
            Label7.Text = "Incorrect Password"
        End If
    End Sub
End Class

Javascript

Here is some javascript which creates this:

<html>
<body>
<script>
function show_equation()
{
var action=prompt("What would you like to do? Add, Subtract, Multiply or Divide?","Add");
var n1=document.vari.no1.value;
var n2=document.vari.no2.value;
switch(action)
{
case (action == "add" || "Add"):
 alert(Number(n1)+Number(n2))
 break;


case (action == "subtract" || "Subtract"): 
 alert(Number(n1)-Number(n2))
 break;
 case (action == "multiply" || "Multiply"):
 alert(Number(n1)*Number(n2))
break;
 case (action == "divide" || "Divide"):
 alert(Number(n1)/Number(n2))
break;
}
}
</script>
<form name="vari">
<input name="no1" type="text">
<input name="no2" type="text">
<input name="calculate" type="button" onclick="show_equation()" value="Calculate" />
</form>
</body>
</html>
</body>
</html>