Make a 🐟 Swim Across Your Browser Tab

fishyTitle.js

var renderIntervalInMillis = 50;
var characterWidth = 80;

var i = 0;
var whitespace = (new Array(characterWidth)).join('\u205f');
setInterval(function() {
  var position = whitespace.length - (i++ % whitespace.length);
  document.title = whitespace.substring(0, position) + '🐟' + whitespace.substring(position + 1);
}, renderIntervalInMillis);