I have an onChange event on one select box (usageDisplays), which populates the next select box based on the selected value of the first:
<html:select name="usageDisplays" property="name" indexed="true" onchange='<%="populateYearsList(" + Id + "," + name + ")"%>' />
This works fine when the user selects the value in usageDisplays, but doesn't work at all when the value of usageDisplays is set based on a radio button choice earlier on the page
getElementByName("usageDisplay.name").value = userName;