boostrap 3 modal , focus input field not working on firefox

Question

I'm using modal from bootstrap 3 where it contains on input field

this modal is being launched using jquery code when page is loaded (not by clicking a button)

$().ready(function()
{
    $('#OTPModal').modal('show');
});

once the modal is shown I'm making the input become focus by this code

$('#OTPModal').on('shown.bs.modal', function () 
{
    $('#OTPField').focus();
});

this code is working fine in google chrome, but it's not in firefox !

check the jsFiddle with chrome and firefox to see the different

firefox version: 63.0.1 (64-bit)

chrome version: Version 70.0.3538.77 (Official Build) (64-bit)

user_838488 · Answer