JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<head>
    <title>Test Page</title>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>
    <div id="main">
        <p id="test"></p>   
    </div>
</body>

CSS

#main {
    width:800px;
    height:800px;
    position:relative;
}

JavaScript

var mainDiv = $('#main'),
    testVal = '';
$('<div class="block"></div>').appendTo(mainDiv).css({
    position: 'absolute',
    zIndex: 10,
    display: 'none',
    width: 30,
    height: 30,
    left: 30,
    top: 30
});
testVal = $('.block').css('left');
$('#test').text(testVal);