jQuery Mobile displays hidden select element

Answer 1

When your page loads, jQuery Mobile enhances your page to have it the mobile look-and-feel. Unfortunately, there is currently an issue with jQuery mobile that it cannot attach custom classes (and even custom styles, by the style attribute) to enhanced elements. Please check https://github.com/jquery/jquery-mobile/issues/3577 for the issue. As a workaround while this issue is still not resolved, you may actually wrap it inside a div element and control the display of the div wrapper instead.