populating radio buttons in JSP

[danglingpointers]

What I would like to do is populate the radio button selections with results from a database query. Here is what I have thus far:

<% //begin JSP, call database %>
<form>
<table>
 <tr>
  <td><input type="radio" value="VAL1" name="button"></td>
  <td><input type="radio" value="VAL2" name="button"</td>
  <td><input type="radio" value="VAL3" name="button"</td>
 </tr>
</table>

<table>
 <tr>
  <td><input type="radio" value="VAL1" name="button1"</td>
  <td><input type="radio" value="VAL2" name="button1"></td>
  <td><input type="radio" value="VAL3" name="button1"></td>
 </tr>

<script>

  document.forms[0].elements['button']['<%= rs.getString("COL_NAME") %>'].checked = true;
  document.forms[0].elements['button1']['<%= rs.getString("COL_NAME") %>'].checked = true;

</script>
</form>
<% // do some more java stuff. %>

When the page loads, I get an error "document.forms.0.elements.button.'VALUE_OF_rs.getString()' is null or not an object.

I have checked my rendered page source and the scriptlets are returning valid values for the radio button element choices. I have tried moving the javascript code to various places around the page and have come up with the same error.

Thanks in advance.

- Tim

 

[rac2]

My guess is that the error message is from the JSP processor, not from the Javascript. I have never seen a message like this

'VALUE_OF_rs.getString()' is null or not an object

and I have seen a lot of Javascript errors, believe me.

If the message is from JSP, then it may mean that the recordset is empty, or that the column has a NULL in the current row of the recordset.

Regarding the Javascript, I think the value must be an integer like

document.forms[0].elements['button'][5].checked = true;

because the elements of a radio group are accessible in an array which uses numerical values for the subscript.

 

[danglingpointers]

rac2,

That was the problem indeed. The "'VALUE_OF_rs.getString()'" wasn't part of the actual error code, but rather that statement evaluated to a single string which was part of the error code. My apologies for the confusion.

Now all I have to do is find a way to enumerate all of the possible values of the element choices. If only I could cross-line javascript and c++...

- Tim

 

[LFI]

Could you use something along the lines of:

[b]<%
 while(rs.getNext())
 {
%>[/b]

<script>
[b]if(document.forms[0].elements['button']['<%= rs.getString("COL_NAME") %>'])
{[/b]
  document.forms[0].elements['button']['<%= rs.getString("COL_NAME") %>'].checked = true;
  document.forms[0].elements['button1']['<%= rs.getString("COL_NAME") %>'].checked = true;
[b]}[/b]
</script>
[b]<%
 }
%>[/b]

The resulting HTML might not be so very pretty, but as long as it doesn't lead to the generation of a thousand if-blocks, it shouldn't be a problem.

--Dave

 

[JontyMC]

Why don't you use:

><input type="radio" value="VAL1" name="button" checked="checked"/>

Instead of using JavaScript. Will work with people who have JavaScript turned off too!

Jon

"I don't regret this, but I both rue and lament it.