<html>
<head>
<title>JSP Data Entry Form </title>
</head>
<body bgcolor="lightyellow">
<h2 align='center'>Data Entry Form - JSP validation on same page</h2>
<%
boolean isFirstTime;
String message = "";
String firstname = request.getParameter("fname");
String lastname = request.getParameter("lname");
String emailAddr = request.getParameter("email");
if (firstname==null && lastname==null && emailAddr==null)
isFirstTime = true;
else
isFirstTime = false;
if (firstname == null) firstname = ""; //http puts null, change to ""
if (lastname == null) lastname = "";
if (emailAddr == null) emailAddr = "";
if (! isFirstTime) //if not first time around
{ //validate entry fields
if (emailAddr.equals(""))
message = "Please enter email address";
if (lastname.equals(""))
message = "Please enter last name";
if (firstname.equals(""))
message = "Please enter first name";
}
%>
<form name='form1' method='GET' action='example3.jsp'>
<fieldset style='width:350px; height:140px; border-color:gold'>
<legend>Join Our Email List</legend>
<table width=350px>
<tr><td><b>First Name </td><td><input type='text' name='fname'
value='<%= firstname %>' /></td></tr>
<tr><td><b>Last Name </td><td><input type='text' name='lname'
value='<%= lastname %>' /></td></tr>
<tr><td><b>Email Address </td><td><input type='text' name='email'
value='<%= emailAddr %>' /></td></tr>
<tr><td><input type='submit' value=' Register ' /></td></tr>
</table>
<font color='red'> <%= message %> </font>
</fieldset>
</form>
<h2>You Entered:</h2>
<table>
<tr><td>First Name: </td><td> <%= firstname %> </td></tr>
<tr><td>last Name: </td><td> <%= lastname %> </td></tr>
<tr><td>Email Address:</td><td> <%= emailAddr %> </td></tr>
</table>
</body>
</html>