Check if first radio button w/jQuery

Question

If i build a list of items with radiobuttons next to them, how do I check the first one by default?

Answer 1

$(".radio_identifier:first").prop('checked', 'checked');

Answer 2

<input type="radio" name="group1" value="a" checked>

Simply include the checked attribute.

Or through jQuery,

$("#groupids:first").prop('checked', 'checked');