[jQuery] parent function value

[jQuery] parent function value


Hello,
I'm new in javascript and jquery, and i need little help.
function checkUsername(name) {
function checkUsername(name) {
                                     $.post(prefix+'/registration/checkUsername',
{username:name.val()},function(data){if (data == 'yes'){name.addClass
('ui-state-error'); updateTips('Username taken'); return false} else
{return true} });
}
How can I set checkUsername to "true" or "false" from function(data)
which is communicating with my php code.
Thanks.