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How to check if textboxes are null

 
Jitesh Ranavaya
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Posts: 9
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Hi, I am writing a 'form' where I need to check if text boxes are null (empty), before the next page is displayed. Here is my code so far:


<%@page import="reg.Register"%>
<jsp:useBean id = "newcust" class="reg.Register" scope ="session"/>

<jsp:setProperty name ="newcust" property="*" />



<% if(request.getParameter("Continue")!=null){

%>

<%!String lname="";%>



<%
if (request.getParameter("lastName")==null){

lname = "Please enter last name";
response.sendRedirect("Register1.jsp");


}
%>


<jsp:forward page="Register2.jsp"/>
<%}%>


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<script language="JavaScript" type="text/JavaScript">
<!--
function MM_reloadPage(init) { //reloads the window if Nav4 resized
if (init==true) with (navigator) {if ((appName=="Netscape")&&(parseInt(appVersion)==4)) {
document.MM_pgW=innerWidth; document.MM_pgH=innerHeight; onresize=MM_reloadPage; }}
else if (innerWidth!=document.MM_pgW || innerHeight!=document.MM_pgH) location.reload();
}
MM_reloadPage(true);
//-->
</script>
</head>

<body>

<span id="Layer1" style="position:absolute; left:610px; top:15px; width:358px; height:23px; z-index:10">
<div align="right"><font color="#0000FF" size="3" face="Lucida Console"><a href="FrontPage.jsp">Home</a>
<a href="SignIn.jsp">Sign In</a> <a href="SignOut.jsp">Sign Out</a> <font color="#000000">Register</font>
Help</font></div>
</span>
<div id="Layer2" style="position:absolute; left:9px; top:82px; width:137px; height:83px; z-index:11">
<table width="146" border="0" cellpadding="2">
<tr>
<td><font color="#0000FF" size="3" face="Lucida Console">My Bazaar</font></td>
</tr>
<tr>
<td><font color="#0000FF" size="3" face="Lucida Console">Browse</font></td>
</tr>
<tr>
<td height="20"><font color="#0000FF" size="3" face="Lucida Console"><a href="Sell.jsp">Sell</a></font></td>
</tr>
<tr>
<td><font color="#0000FF" size="3" face="Lucida Console">Search</font></td>
</tr>
</table>
</div>

<div id="Layer3" style="position:absolute; left:785px; top:509px; width:96px; height:17px; z-index:15"><font color="#FF0000" face="Lucida Console">*</font><font color="#FF0000">required
fields</font></div>
<form method = post action = "Register1.jsp">
<div id="Layer5" style="position:absolute; left:191px; top:126px; width:351px; height:255px; z-index:14"> <form name="form1" method="post" action="">
<table width="342" height="389" border="0" cellpadding="2">
<tr>
<td width="63"><font color="#FF0000" face="Lucida Console">*</font><font face="Lucida Console">Title
: </font></td>
<td width="145"><font face="Lucida Console">
<select name="title">
<option>Mr</option>
<option>Mrs</option>
<option>Ms</option>
</select>
</font></td>
</tr>
<tr>
<td><font color="#FF0000" face="Lucida Console">*</font><font face="Lucida Console">Surname
: </font></td>
<td><font face="Lucida Console">


<%=lname%>


<input name="lastName" type="text" id="lastName">
</font></td>
</tr>
<tr>
<td><font color="#FF0000" face="Lucida Console">*</font><font face="Lucida Console">Firstname
: </font></td>
<td><font face="Lucida Console">
<input name="firstName" type="text" id="firstName">
</font></td>
</tr>
<tr>
<td height="52"><font color="#FF0000" face="Lucida Console">*</font><font face="Lucida Console">Street
Address : </font></td>
<td><font face="Lucida Console">
<input name="addressLine1" type="text" id="addressLine1">
</font></td>
</tr>
<tr>
<td><font face="Lucida Console"> </font></td>
<td><font face="Lucida Console">
<input name="addressLine2" type="text" id="addressLine1">
</font></td>
</tr>
<tr>
<td><font color="#FF0000" face="Lucida Console">*</font><font face="Lucida Console">City
: </font></td>
<td><font face="Lucida Console">
<input name="city" type="text" id="city">
</font></td>
</tr>
<tr>
<td><font color="#FF0000" face="Lucida Console">*</font><font face="Lucida Console">County
: </font></td>
<td><font face="Lucida Console">
<input name="county" type="text" id="county">
</font></td>
</tr>
<tr>
<td><font color="#FF0000" face="Lucida Console">*</font><font face="Lucida Console">Postcode
: </font></td>
<td><font face="Lucida Console">
<input name="postCode" type="text" id="postCode">
</font></td>
</tr>
<tr>
<td><font color="#FF0000" face="Lucida Console">*</font><font face="Lucida Console">Phone
number :</font></td>
<td><font face="Lucida Console">
<input name="phone" type="text" id="phone">
</font></td>
</tr>
<tr>
<td><font color="#FF0000" face="Lucida Console">*</font><font face="Lucida Console">Country
: </font></td>
<td><font face="Lucida Console">
<input name="Country" type="text" id="Country">
</font></td>
</tr>
<tr>
<td><font color="#FF0000" face="Lucida Console">*</font><font face="Lucida Console">Date
of Birth : </font></td>
<td><font face="Lucida Console">
<input name="dob" type="text" id="dob">
</font></td>
</tr>
<tr>
<td><font face="Lucida Console"> </font></td>
<td><font face="Lucida Console">
<input name="Continue" type="submit" id="Continue" value="Continue">
</font></td>
</tr>
</table>
</form>
</div>
<div align="right"></div>
<span id="Layer9" style="position:absolute; left:613px; top:33px; width:172px; height:38px; z-index:9"><img src="l.jpg" width="389" height="48"></span>
<div align="right">
<p> </p>
<p align="left">  </p>
</div>
</body>
</html>

The above does not work (and you can probably tell that am new to jsp).
lname is the attribute that I want to display the error message, obviously above the lastName text box. The problem I am having is that I dont know how to stucture the if (if-else) statements.

Thanks for the help in advance
Jitesh
 
Srinivasa Raghavan
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Hope you can use a JavaScript, that validates your form on submit and return false if there is any error, else return true..
[ November 08, 2004: Message edited by: srini vasan ]
 
William Brogden
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The content of type="text" inputs is never null, you will get an empty string "" if the user does not fill it in.
Bill
 
Jitesh Ranavaya
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William, thats what I meant, an empty string.
How do I check that all of the text boxes are filled in and not left blank?
There must be an efficient way of doing it.
 
Tim Holloway
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Actually, I prefer to check not only empty, but blank:

 
pradeep jaladi
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After submitting the Values forward to the validation.jsp in that validate the parameters if any parameter is null or Blank simply .redirect it back to ur First page or forward to the next page.
 
Maki Jav
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Hi,

You check for empties in a javascript function eg you have a form named
frm1 with a text field named myname and a submit button.

Point:
You may either use
1) length of textfield value or
2) text of textfield
to check out the textfield.

Here is an example:

Hope this solves your problem.

Maki Jav
[ December 18, 2004: Message edited by: Maki Jav ]
 
Eric Pascarello
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Using JavaScript should not be your option since it can be disabled. Yes you can use it, but you should always have the checks with your server side code.

Eric
 
Nitin Jawarkar
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hi jitesh,

U must use javascript for validation becoz it work on client side so u r request processing will fast.
Thanx
 
Bear Bibeault
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Nitin,

JavaRanch is a community of people from all over the world, many of who are not native English speakers. While using abbreviations like "u" instead of spelling out "you" is convenient when text messaging your friends on a cell phone or in a chat room, it presents an extra challenge to those that are already struggling with English. Additionally, such shortcuts may confound automated translation tools that patrons of the Ranch may be making use of.

I would like to ask for your help in making the content of JavaRanch a little easier to read for everybody that visits here by not using such abbreviations.

thanks,
bear
JSP Forum Bartender
 
Bear Bibeault
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U must use javascript for validation becoz it work on client side so u r request processing will fast.


If, by this, you mean that by performing validation on the client you can forgoe server-side validation (to make server-side processing faster), then this is very poor advice indeed.

Always, always, ALWAYS, and did I mention always perform server-side validation regardless of whether you perform client-side validation. Not only can Javascript be turned off, script kiddies just love to probe your site by spoofing requests looking for vulnerabilities.
 
Nitin Jawarkar
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Thanx Bear,

For suggesting me.
 
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