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Old August 25th, 2008, 03:01 PM
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Default VBscript boolean function causes Javscript to bomb

Hi there

I have a server-side VB that runs at the beginning of the asp page, and it returns a result set, call it loResultSet.

In the client side javscript, I was trying to check to see if this result set is nothing or not.

 if (<%=(loResultSet is nothing)%>)


// javscript code


However it bombs because that (loResultSet is nothing) returns "True", as opposed to "true", and Javascript doesn't recognize True.

I know this is a dumb question, but how would you fix this, and I mean, not in a hack way, such as

if (%=(loResultSet is nothing)%>.toString().toLowerCase())

Many thanks appreciated.


Old August 25th, 2008, 03:10 PM
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Well, the toLowerCase() is ugly to the eye, but it's actually pretty effective.

All the other solutions will involve more code.

You might want to create a custom function just for this purpose:

Function JSBoolean( test As Boolean ) Returns String
    If test Then Return "true"
    Return "false"
End Function

You could, of course, do it with IIF:
if ( <%= IIF( loResultSet is nothing, "true", "false" )%> )

But I think I like
if ( <%= JSBoolean(loResultSet is nothing) %> )

Finally, you *could* do the test in your VB code!

<% If loResultSet is Nothing Then %>
... js code for true condition ...
<% Else %>
... js code for false condition ...
<% End If %>

And that's actually the most efficient. No point in sending JS code to the browser when it won't be used.
Old August 25th, 2008, 03:38 PM
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Thanks OldPendant, for your very quick reply.

We have now to change some of our codes to javascript from vbscript because of Firefox incompatibility, that's why I'm changing all the client-code. Thankfully don't have to change the server-code, that at least reduces my workload in half. :)

You're right, there doesn't seem to be one elegant solution; but at least you gave me some good pointers!


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