The method is similar. In this example, assume there were 5 questions in form id=”frm1″, each with more than 1 radio option as a possible response.


function validate() {
  var theform = document.getElementById("frm1");

  //check radio boxes
  var setflag;
  setflag = false;
  
  for (i=1; i<6; i++)      // N questions + 1
  {
    for (j=0; j<theform.elements["q"+i].length; j++)
    {
      if (theform.elements["q"+i][j].checked)
      {
        setflag = true;
      }
    }

    if (setflag == false)
    {
      alert("Please Answer Question #" + i);
      theform.elements["q"+i][0].focus();
      return false;
    }

    setflag = false;
  }
   }


It’s as easy as that

Enjoy.