var i='gecko';
var interval=2;
var his=0;setInterval(function(){var xx=document.querySelectorAll('#chatList>div'); for (var k = 0; k < xx.length; k++) { var text = xx[k].innerText.substr(8); text=text.substr(text.indexOf(':')+1); var r = new RegExp(i, 'i'); if (text.match(r)&&k>his) { his = k;var audio = document.createElement('audio'); var source = document.createElement('source'); audio.setAttribute('autoplay',''); source.src='http://www.w3schools.com/html/horse.mp3'; audio.appendChild(source); document.querySelector('body').appendChild(audio); } };},interval*1000);