How to set the focus for a particular field in a Bootstrap modal, once it appears

Try this

Here is the old DEMO:

EDIT:
(Here is a working DEMO with Bootstrap 3 and jQuery 1.8.3)

$(document).ready(function() {
    $('#modal-content').modal('show');
    $('#modal-content').on('shown', function() {
        $("#txtname").focus();
    })
});

Starting bootstrap 3 need to use shown.bs.modal event:

$('#modal-content').on('shown.bs.modal', function() {
    $("#txtname").focus();
})