JS does not seem to recognize null hidden value within table

celia05es

Apr 18th 2007, 4:15 am

I have the following code:

<html>
<head>
<title>TEST</title>
<script language="javascript">
function getFields(index)
{
var num=1;
if (index !=0)
num=2*index +1;
return num;
}

function show(line)
{
var num=getFields(line);
id=document.forms[0].elements[num-1].value;
alert("id read with elements[num]="+id);
if (id == null)
alert("1. ID NULL");

id=document.forms["0"].elements["serv_"+line].value;
alert("id read with elements[name]="+id);
if (id == null)
alert("2. ID NULL!");
}
</script>
<body>
<%@page language="java" %>
<center>
<form onSubmit="return false" method="post" name="my_form" action="">
<table border=2>
<tr>
<td id='c_0' onclick='show(0)'>
<input type=hidden value=null name="serv_0">
<input type=text readonly value="1" size=25>
</td></tr>
<tr>
<td id='c_1' onclick='show(1)'>
<input type=hidden value="SERV" name="serv_1">
<input type=text readonly value="2" size=25>
</td></tr>
</table>
</form>
</body>
</html>

Results:
1. When I click on the 1st cell, the alarms that are being fired are:
- id read with elements[num] = null
- id read with elements[name] = null

AS YOU CAN SEE JS DOES NOT RECOGNIZED NULL!

2. When I click on the 2nd cell,
- id read with elements[num] = SERV
- id read with elements[name] = SERV

ajsa52

Apr 18th 2007, 9:05 am

You should enclose your attribute values using double quotes, and instead of using null you should use an empty string: ""
So, you should check against that empty string "", not null.

replace this:

<input type=hidden value=null name="serv_0">
<input type=text readonly value="1" size=25>

with this:

<input type="hidden" value="" name="serv_0">
<input type="text" readonly="true" value="1" size="25">