<html>
<body><div id="countdown"></div><div id="notifier"></div><script type="text/javascript">function startTimer() { userInput = document.getElementById('userTime').value; if(userInput.length == 0){ alert("Please enter a value"); } else { var numericExpression = /^[0-9]+$/; if(!userInput.match(numericExpression)){ alert("Please enter a number") } else { function display( notifier, str ) { document.getElementById(notifier).innerHTML = str; } function toMinuteAndSecond( x ) { return Math.floor(x/60) + ":" + x%60; } function setTimer( remain, actions ) { (function countdown() { display("countdown", toMinuteAndSecond(remain)); actions[remain] && actions[remain](); (remain -= 1) >= 0 && setTimeout(arguments.callee, 1000); })(); } setTimer(userInput, { 10: function () { display("notifier", "Just 10 seconds to go"); }, 5: function () { display("notifier", "5 seconds left"); }, 0: function () { display("notifier", "Time is up"); } }); } }}</script>Please Enter A Number: <input type="text" id="userTime" /><input type="button" value="Go" onclick="startTimer()" /></body> </html>