how to get radio button value in javascript--

[selvialagar]

my code doesn't work. undefined is displayed.....h ow to get a value of radoi button in javascript

[HTML]function enableaddr()
{
alert(document. getElementById( 'reason').lengt h);
for (var i=0; i < document.getEle mentById('reaso n').length; i++)
{
if (document.getEl ementById('reas on[i]').checked)
{
var reason1 = document.getEle mentById('reaso n[i]').value;
alert(reason1);
}
}
}

<form action="cust_in dex.php?action= delete&cid=<?ph p echo $cid;?>" name="del_form" >
<table width="400" border="0" cellpadding="6" align="center" cellspacing="1" class="bg1">
<tr class="bg2"><td >Enter the reason to delete the record with the customer name <?php echo $name;?> :</td></tr>
<tr class="bg2"><td ><input type="radio" name="reason" id="reason" value="close" onclick="enable addr()" />Close</td></tr>
<tr class="bg2"><td ><input type="radio" name="reason" id="reason" value="shifta" onclick="enable addr()" />Shift &nbsp;</td></tr>
<tr class="bg2"><td >Enter the address :&nbsp;&nbsp;&n bsp;<textarea cols="30" rows="4" disabled="disab led" name="shiftaddr ess" id="shiftaddres s"></textarea></td></tr>
<tr class="bg2"><td align="center"> <input type="submit" value="submit" class="button"> </td></tr>
<input type="hidden" name="reason1" id="reason1" />
</table>
</form>[/HTML]

[gits]

you make the wrong use of getElementById( ). first, the id HAS TO be unique in a page ... and so the method could give you just ONE element. you may use something that retrieves you a node list like in the following example:

[CODE=javascript]function enableaddr() {
var reasons = document.getEle mentsByName('re ason');

for (var i = 0; i < reasons.length; i++) {
if (reasons[i].checked) {
var reason1 = reasons[i].value;
alert(reason1);
}
}
}
[/CODE]
kind regards