I use Java 7, Struts 1.2.7, Servelt 2.4, JSP 1.2
I have an Action adminHome.do and a jsp page adminHome.jsp
This is adminHome.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Admin Home</title>
</head>
<body>
<table bgcolor="white" border=0 cellpadding=2 cellspacing=2>
<html:form action="/adminHome.do" method="post">
<tr><td class="lightblue" align=right>email: </td>
<td><html:text size="40" property="email"/></td></tr>
<tr><td class="lightblue" align=right>first name: </td>
<td><html:text size="40" property="firstName"/></td></tr>
<tr><td class="lightblue" align=right>last name: </td>
<td><html:text size="40" property="lastName"/></td></tr>
<tr><td class="lightblue" align=right>user id: </td>
<td><html:text size="40" property="userId"/></td></tr>
<tr><td class="lightblue" align=right>competition: </td>
<td><html:select property="competitionId">
<c:forEach var="competition" items="${competitionsSorted}">
<html:option value="${competition.competitionId}">${competition}
</html:option>
</c:forEach>
</html:select></td></tr>
<tr><td align=center colspan=2><br/>
<html:submit property="submit" value="search"/>
</td>
</tr>
</html:form>
</table>
</body>
</html>
admin form searching of user example
+-----------------+------------------------+
| Email | |
+-----------------+------------------------+
| First Name | |
+-----------------+------------------------+
| Last Name | |
+-----------------+------------------------+
| User | 123 | <- UserID = 123
+-----------------+------------------------+
| Competition | Competition 1 |
+-----------------+------------------------+
| Competition 2 |
| Competition 3 | <- drop down list
| Competition 4 |
+----------------+
In this admin form
I want to have disabled competition drop down list if userId is not empty.
This can be done with plain javascript.
Below code should work for you.
Let me know if you have any further questions.