Javascript Radio Button Values returns undefined
Question
I am having lots of difficulty with getting the value from a radio button group in Javascript. I have searched for hours and have not found the solution. When I try to do a document.write command to show what the value is from the radio button selection, they all come back as "undefined". But the funny thing is, if I select the first radio button, it does come back with the correct value shown. This is part of my frustration and I haven't found the solution to find out how to get the other values in the radio button group, this should be SIMPLE! Your help will be greatly appreciated.
Please take a close look at my Javascript code to try to get the value (please disregard the return false; command as I use it to stop the rest of the code on my page):
for( i = 0; i < document.forms.incident.elements.model.length; i++ )
{
if(document.forms.incident.elements.model[i].checked)
var omodcheck = document.forms.incident.elements.model.value;
document.write(omodcheck);
return false;
}
My HTML form name is incident. The form code for the radio button group is as follows:
Laptop Model:
<input type="radio" name="model" value="Lenovo X200" />Lenovo X200<br />
<input type="radio" name="model" value="Lenovo X201" />Lenovo X201<br />
<input type="radio" name="model" value="Lenovo X200T" />Lenovo X200T<br />
<input type="radio" name="model" value="Lenovo X201T" />Lenovo X201T<br />
<input type="radio" name="model" value="Lenovo T400" />Lenovo T400<br />
<input type="radio" name="model" value="Lenovo R400" />Lenovo R400<br />
In this case, the code for the document.write(omodcheck) returns the value "Lenovo X200", however, if I make a selection for any of the other radio buttons, the value comes back "undefined"!
Please help!
2 answers
solution1
1 2013-07-24 09:47:16
If I understand it correctly, you will need something like this:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<script type="text/javascript">
function checkChecked(){
for (var i = 0; i< document.getElementsByName('model').length; i++) {
if(document.testform["model"][i].checked){
var omodcheck = document.testform["model"][i].value
alert(omodcheck);
}
}
}
</script>
</head>
<body onload="checkChecked()">
Laptop Model:
<form name="testform">
<input type="radio" name="model" value="Lenovo X200" onchange="checkChecked()" />Lenovo X200<br />
<input type="radio" name="model" value="Lenovo X201" onchange="checkChecked()" />Lenovo X201<br />
<input type="radio" name="model" value="Lenovo X200T" onchange="checkChecked()" />Lenovo X200T<br />
<input type="radio" name="model" value="Lenovo X201T" onchange="checkChecked()" />Lenovo X201T<br />
<input type="radio" name="model" value="Lenovo T400" onchange="checkChecked()" />Lenovo T400<br />
<input type="radio" name="model" value="Lenovo R400" onchange="checkChecked()" checked />Lenovo R400<br />
</form>
</body>
</html>
or
use brackets on your if condition:
for( i = 0; i < document.forms.incident.elements.model.length; i++ )
{
if(document.forms.incident.elements.model[i].checked){
var omodcheck = document.forms.incident.elements.model[i].value;
document.write(omodcheck);
}
}
solution2
0 2013-07-24 09:44:07
From what I understand, it's a very small mistake in that the for-loop is ending on your return false statement. The return false must be outside of the for loop.
Take a look at this jsfiddle (slightly modified to use alert() instead of document.write();
btnSubmit.onclick = function(){
for( i = 0; i < document.forms.incident.elements.model.length; i++ )
{
if(document.forms.incident.elements.model[i].checked)
var omodcheck = document.forms.incident.elements.model.value;
}
alert(omodcheck);
return false;
}
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