JSFiddle - React, Tailwind, and code Playground

HTML

<div id='footer' style='position: absolute; display: none;'>I am a footer</div>

JavaScript

$(function(){
    $(window).resize(function(e){
        placeFooter();
    });
    placeFooter();
    // hide it before it's positioned
    $('#footer').css('display','inline');
});

function placeFooter() {    
    var windHeight = $(window).height();
    var footerHeight = $('#footer').height();
    var offset = parseInt(windHeight) - parseInt(footerHeight);
    $('#footer').css('top',offset);
}