How can I check whether a radio button is selected with JavaScript?

Question

I have two radio buttons within an HTML form. A dialog box appears when one of the fields is null. How can I check whether a radio button is selected?

Answer 1

This is also working, avoiding to call for an element id but calling it using as an array element.

The following code is based on the fact that an array, named as the radiobuttons group, is composed by radiobuttons elements in the same order as they where declared in the html document:

if(!document.yourformname.yourradioname[0].checked 
   && !document.yourformname.yourradioname[1].checked){
    alert('is this working for all?');
    return false;
}