Hi, I am trying to create some javascript that will let the user enter a date (possibly using a date picker) and a time. When the user hit submit I want the timer to countdown to that date and sound an alarm at the time. I have the following bit of code that will allow the user to enter an number of seconds but I am haveing trouble expanding on this and getting a date picker involved so the user can enter an exact date and time. Any help would be great

Code:
    <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 () { alert("you can smoke now");       }
                                 }); 
                    }  
                }
            }
            </script>
        Please Enter A Number: <input type="text" id="userTime" />
        <input type="button" value="Go" onclick="startTimer()" />
    </body>