// jQuery version 1.6 or above use:
$("#myRadioID").prop("checked", true);
//jQuery versions below 1.6 use:
$("#myRadioID").attr('checked', 'checked');$('#element').click(function() {
if($('#radio_button').is(':checked')) { alert("it's checked"); }
});
$(document).ready(function(){
$('#submit_button').click(function() {
if (!$("input[name='name']:checked").val()) {
alert('Nothing is checked!');
return false;
}
else {
alert('One of the radio buttons is checked!');
}
});
});//<input type="radio" name="book_condition" value="3" >
$("input:radio[value='3'][name='book_condition']").prop('checked',true);