I\'m currently extending the lavalamp plugin to work on dropdown menus but I\'ve encountered a small problem. I need to know the offsetWidth of an element that
The width of an element that has CSS visibility: hidden is measurable. It's only when it's display: none that it's not rendered at all. So if it's certain the elements are going to be absolutely-positioned (so they don't cause a layout change when displayed), simply use css('visibility', 'hidden') to hide your element instead of hide() and you should be OK measuring the width.
Otherwise, yes, show-measure-hide does work.