Relying on the following attributes as returned from .attr() will break, and should get ported to use .prop() instead: 'checked', 'disabled', 'readonly', 'selected' (for <option>s), 'multiple' (for <select>s), 'ismap' (for <img>s), 'defer', 'noresize' (for <frame>s), 'nowrap'.

List compiled (partially) from http://stackoverflow.com/questions/706384/boolean-html-attri...