index.html

<style>
#textLog{
    width:100%;
    height:300px;
}
</style>
<script src="app.js"></script>
<h1>WebWorkers</h1>
<textarea id="textLog" readonly></textarea>
<button id='start1'>Run Script</button>
<script>

    var button1 = document.getElementById("start1");
    var log1 = document.getElementById("textLog");

/*** Example of appWorker implementation ***/
    var callbackfunction = function(x){
        log1.value = "Seconds: " + x;
    }

    button1.addEventListener("click",function(){
        log1.value = "Script Started";
        appWorker.make("counter","counter.js");
        appWorker.run("counter","start",callbackfunction)
    });
/*******************************************/
    log1.value = (window.Worker)? "window.Worker = " + window.Worker : "Worker not available on this browser";

</script>