How to check if a value is defined?

[georgeu2000]

The following code is raising an error:

input = element.children( "input[ name='name' ]" )
if input.attr( 'type' ) == 'radio'
  ...

This works fine, except sometimes type is undefined:

'undefined' is not an object (evaluating 'input.$attr("type")['$==']')

What is a good way to protect the if statement from undefined values? I guess the JS way is typeof( input.attr( 'type' )) == 'undefined', but not sure how to generate this from Ruby.

I tried defined() and .nil? but they don't seem to do this check. Perhaps there is one way (or there should be) one way of doing this?

[meh]

That's a problem caused by the library you're using (I assume opal-jquery).

[georgeu2000]

OK, thank you.