Assigned width in percentage but want to get it in pixels

Answer 1

It could have been a bug in earlier jQuery versions, up to this Github PR: https://github.com/jquery/jquery/pull/3741

Although it's 2019 now, I had to use jQuery 1.12.4 and noticed that width computation of a hidden (hidden by parent) element was always 100.

By debugging, I found that the jQuery outerWidth (similar for innerHeight, innerWidth, height, width, outerHeight and outerWidth) function will call the width cssHook, which in turn calls getWidthOrHeight(). getWidthOrHeight() may obtain a width in %, which is then returned as it is. The width function does not check what was returned and passes it through parseFloat, which results in the 100% becoming just 100.