Web Workers allow you to run JavaScript code in the background without blocking the web page user interface. Web workers can improve the overall performance of a web page and also enhance the user experience.

In the example below, the intensive work is in the script lengthytask.jsand it is invoked through a button click. This runs in the background without impacting the performance of the web page.

$(document).ready(function () {      if (Modernizr.webworkers)      {          $("#buttonCompute").click(function () {                var worker = new Worker("scripts/lengthytask.js");                worker.addEventListener("message", function (evt) {                     //cb                },false);                worker.postMessage();            });        });