Hide dependent drop down

In PHPRunner 10.4 I have three cascading dependent drop down lists on the search panel in list page. Is it possible to grey out the dependent dropdown until the master is selected? In the Javascript on load event for list page the code below will remove the dependent dropdown. I want to disable the dependent until master is selected.

var srch = pageObj.getSearchController();
var field1 = srch.getSearchFields("Division")[0];
var field2 = srch.getSearchFields("IDPlant")[0];
field2.remove("IDPlant");