var player; // Define "player" var to make my code linter happy function start() { // Start Web Worker & send song data to player var logs = document.getElementById('progress'); // Define log element window.logs = logs; // Make variable Global window.logs.value = ""; // Create Web Worker if it doesn't already exist if (window.Worker && typeof(player) == "undefined") { var player = new Worker("worker.js"); window.player = player; // Make variable Global player.onmessage = function(event) { var data = event.data; console.log(data) window.logs.value += "x\n"; }; // Send song data to player var song = document.getElementById("tune").innerHTML; player.postMessage(song); } } function end() { // Stops the Web Worker window.logs.value = ""; player.terminate(); }