JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html>
<head>
  <link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css" rel="stylesheet" type="text/css"/>
  <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.5/jquery.min.js"></script>
  <script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js"></script>


</head>
<body style="font-size:62.5%;">
  <input type="text" id="amount" style="border:0; color:#f6931f; font-weight:bold;" />

<div id="slider"></div>

</body>
</html>

CSS

#slider { margin: 10px; }

JavaScript

function addCommas(numberString) {
  var resultString = numberString + '',
      x = resultString.split('.'),
      x1 = x[0],
      x2 = x.length > 1 ? '.' + x[1] : '',
      rgxp = /(\d+)(\d{3})/;

  while (rgxp.test(x1)) {
    x1 = x1.replace(rgxp, '$1' + ',' + '$2');
  }

  return x1 + x2;
}

$(function() {
         $( "#slider" ).slider({
             value:100,
             min: 0,
             max: 5000000000,
             step: 1,
             slide: function( event, ui ) {
                 $( "#amount" ).val( "£" + addCommas(ui.value) );
             }
         });
         $( "#amount" ).val( "£" + $( "#slider" ).slider( "value" ) );
     });