how to set radio option checked onload with jQuery

Question

How to set radio option checked onload with jQuery?

Need to check if no default is set and then set a default

Answer 1

Say you had radio buttons like these, for example:

<input type='radio' name='gender' value='Male'>
<input type='radio' name='gender' value='Female'>

And you wanted to check the one with a value of "Male" onload if no radio is checked:

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

Answer 2

How about a one liner?

$('input:radio[name="gender"]').filter('[value="Male"]').attr('checked', true);