how to check whether radio button is selected or not in javascript code example

Example 1: check if radio button is checked

$('#element').click(function() {
   if($('#radio_button').is(':checked')) { alert("it's checked"); }
});

Example 2: js check if radio button is checked

if(document.getElementById('gender_Male').checked) {
  //Male radio button is checked
}else if(document.getElementById('gender_Female').checked) {
  //Female radio button is checked
}