How to get user selected value in the radio button using JQuery.Here tested easy best methods to selected radio button value.
HTML code is here.

<input class="radioBtnClass" name="numbers" type="radio" value="1" />1
<input class="radioBtnClass" name="numbers" type="radio" value="2" />2
<input class="radioBtnClass" name="numbers" type="radio" value="3" />3

JQuery Code

if($("input[type='radio'].radioBtnClass").is(':checked')) {
   var selected_value =  $("input[type='radio'].radioBtnClass:checked").val();
   alert(selected_value);
}

This is also working.

$(".radioBtnClass").change(function(){
      // bind a function to the change event
        if( $(this).is(":checked") ){ // check if the radio is checked
            var selected = $(this).val(); // retrieve the value
            alert(selected_value);
        }
});