Answers for "get the element after radio button javascript"

get value of selected radio button using javascript

document.getElementById('submit').onclick = function() {
    var radios = document.getElementsByName('contact');
    for (var radio of radios)
    {
        if (radio.checked) {
            alert(radio.value);
        }
    }
}

document get element by id radio button

var selectedOption = $("input:radio[name=option]:checked").val()