Javascript Prototype .visible() method not working in Internet Explorer

I'm using the Prototype (and script.aculo.us) javascript library - since it's what comes with Rails "as standard" - and having a problem with the following snippet:

function show_hide_selects()
{
  chkbox = document.getElementById('game_random_select')
  seldiv = document.getElementById('card_selects')

  if (chkbox.checked && seldiv.visible())
  {
    Effect.BlindUp('card_selects', {duration: 0.5})
    Effect.BlindDown('random_options', {duration: 0.5})
  }
  else if (!chkbox.checked && !seldiv.visible())
  {
    Effect.BlindUp('random_options', {duration: 0.5})
    Effect.BlindDown('card_selects', {duration: 0.75})
  }
}

This snippet is fired onClick for the 'game_random_select' checkbox which controls whether the user wants to specify a list of card-names, or leave the server to make a random choice. It should hide the irrelevant set of form elements, and show the relevant set.

This works fine in FireFox, but doesn't work in Internet Expl开发者_如何学运维orer (tested IE 8). It throws an error "Object doesn't support this property or method" on one of the if-test lines; using the JS debugger indicates that it's seldiv.visible() that doesn't work.

How can I detect the visibility of the element in IE - surely Prototype should be completely compatible with IE? Or am I never going to be able to manage it with Prototype, and should switch to jQuery - which would obviously be Effort, since I'll need to get Rails to comply as well.

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Huh. Sorted this myself, thanks to reading the API documentation and spotting something I wasn't doing.

seldiv.visible() doesn't work, but $('card_selects').visible() does.

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You can try getStyle http://www.prototypejs.org/api/element/getStyle, it will return null if the element has a display property of none.