JSFiddle - React, Tailwind, and code Playground

HTML

<div id='wrapper'></div>
<div id='button'>Click Here</div>
<div id='output'></div>

CSS

#wrapper {
    display: none;
    background: #aaa;
    width: 170px;
    padding: 20px;
}

JavaScript

$(function() {
    $('input').live('focusin', function() {
        $('#output').html('focusin'); // Why this not happens ?
    });
    $('#button').click(function() {
        $('#button').hide();
        build_inputs();
    });    
});
function build_inputs() {
    var html = "<input type='text' /> \
                <br /> \
                <input type='text' />";
    $('#wrapper').append(html);
    $('#wrapper').fadeIn(500, function() {
        $('input:first').focus().trigger('focusin');
    });
}