Answers for "how to check if the radio button is the correct one in javascript"

javascript check radio button

// Native JS solution:
document.getElementById("_1234").checked = true;
// JQuery solution:
$("#_1234").prop("checked", true);

check if one of the radio button is checked

if ($('input[name='+ radioName +']:checked').length) {
           // at least one of the radio buttons was checked
           return true; // allow whatever action would normally happen to continue
      }
      else {
           // no radio button was checked
           return false; // stop whatever action would normally happen
      }