Use Web Workers to Do the Script-intensive Work in the Background

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();
            });
        });