How to toggle display of select

How to toggle display of select

Hello

I have two drop downs in my app. Initially second drop down box is empty. Based on the selection from first select, then second select is populated dynamically.

I came across this posting jQuery Mobile displays hidden select element

As per this posting I was able to hide the second select initially using the ui-screen-hidden is a jquery mobile defined class.

But how do I set display:block when it is populated?

Joe