JSFiddle - React, Tailwind, and code Playground

by walker

HTML

<!--worker-->
<script id="worker1" type="javascript/worker">
    self.onmessage=function(e){
        for(var i=0;i<500000;i++){
            self.postMessage(i);
        };
        self.postMessage('done');
    };
</script>
<input type="button" onclick="sendmsg();" value="worker" /><span id="timespan"></span>

JavaScript

var bb = new Blob([document.querySelector('#worker1').textContent]);
var worker=new Worker(window.URL.createObjectURL(bb.slice()));

worker.onmessage=function(e){
    //var t=document.querySelector('#timespan');
    //t.innerText=e.data;
    if(e.data=='done') console.timeEnd(1);
}

function sendmsg(){
    console.time(1);
    worker.postMessage('');
}