how to read radio button value in javascript code example

Example 1: get radio button value javascript

document.querySelector('input[name="rate"]:checked').value;

Example 2: radio button group get value javascript

$('input[name=gender]:checked').val();

Example 3: javascript on click radio button get value

if (document.getElementById('r1').checked) {
  rate_value = document.getElementById('r1').value;
}