Answers for "input radio with jquery"

jquery select radio

$(function() {
    var $radios = $('input:radio[name=gender]');
    if($radios.is(':checked') === false) {
        $radios.filter('[value=Male]').prop('checked', true);
    }
});

click on a radio button using jquery

$('input:radio[name=sex]:nth(0)').attr('checked',true);
or
$('input:radio[name=sex]')[0].checked = true;