How to set count down in jquery

<script type="text/javascript">

function cdtime(container, targetdate){
if (!document.getElementById || !document.getElementById(container)) return
this.container=document.getElementById(container)
this.currentTime=new Date()
this.targetdate=new Date(targetdate)
this.timesup=false
this.updateTime()
}

cdtime.prototype.updateTime=function(){
var thisobj=this
this.currentTime.setSeconds(this.currentTime.getSeconds()+1)
setTimeout(function(){thisobj.updateTime()}, 1000) //update time every second
}

cdtime.prototype.displaycountdown=function(baseunit, functionref){
this.baseunit=baseunit
this.formatresults=functionref
this.showresults()
}

cdtime.prototype.showresults=function(){
var thisobj=this


var timediff=(this.targetdate-this.currentTime)/1000 //difference btw target date and current date, in seconds
if (timediff<0){ //if time is up
this.timesup=true
this.container.innerHTML=this.formatresults()
return
}
var oneMinute=60 //minute unit in seconds
var oneHour=60*60 //hour unit in seconds
var oneDay=60*60*24 //day unit in seconds
var dayfield=Math.floor(timediff/oneDay)
var hourfield=Math.floor((timediff-dayfield*oneDay)/oneHour)
var minutefield=Math.floor((timediff-dayfield*oneDay-hourfield*oneHour)/oneMinute)
var secondfield=Math.floor((timediff-dayfield*oneDay-hourfield*oneHour-minutefield*oneMinute))
if (this.baseunit=="hours"){ //if base unit is hours, set "hourfield" to be topmost level
hourfield=dayfield*24+hourfield
dayfield="n/a"
}
else if (this.baseunit=="minutes"){ //if base unit is minutes, set "minutefield" to be topmost level
minutefield=dayfield*24*60+hourfield*60+minutefield
dayfield=hourfield="n/a"
}
else if (this.baseunit=="seconds"){ //if base unit is seconds, set "secondfield" to be topmost level
var secondfield=timediff
dayfield=hourfield=minutefield="n/a"
}
this.container.innerHTML=this.formatresults(dayfield, hourfield, minutefield, secondfield)
setTimeout(function(){thisobj.showresults()}, 1000) //update results every second
}



function formatresults(){
if (this.timesup==false){//if target date/time not yet met
var displaystring=arguments[0]+" days "+arguments[1]+" hours "+arguments[2]+" minutes "+arguments[3]+" seconds left until March 23, 2009 18:25:00"
}
else{ //else if target date/time met
var displaystring="Future date is here!"
}
return displaystring
}

function formatresults2(){
if (this.timesup==false){ //if target date/time not yet met
var displaystring="<ul><li>"+arguments[0]+" <span>days</span></li><li> "+arguments[1]+" <span>hours</span></li><li> "+arguments[2]+" <span>minutes</span></li><li> "+arguments[3]+" <span>seconds</span></li></ul>"
}
else{ //else if target date/time met
var displaystring="" //Don't display any text
alert("Christmas is here!") //Instead, perform a custom alert
}
return displaystring
}

</script>


<div id="countdowncontainer"></div>
<br />
<div id="countdowncontainer2"></div>

<script type="text/javascript">
//var future_date = "January 25, 2014 15:10:25";
//var future_date = "February 25, 2014 15:10:25";
//var future_date = "March 25, 2014 15:10:25";
//var future_date = "April 25, 2014 15:10:25";
//var future_date = "May 25, 2014 15:10:25";
//var future_date = "June 25, 2014 15:10:25";
//var future_date = "July 25, 2014 15:10:25";
//var future_date = "August 25, 2014 15:10:25";
//var future_date = "September 25, 2014 15:10:25";
var future_date = "October 25, 2014 15:10:25";
//var future_date = "November 25, 2014 15:10:25";
//var future_date = "December 22, 2014 15:10:25";

/*var futuredate=new cdtime("countdowncontainer", "June 28, 2009 18:25:00")
futuredate.displaycountdown("days", formatresults)*/

var currentyear=new Date().getFullYear()
//dynamically get this Christmas' year value. If Christmas already passed, then year=current year+1
var thischristmasyear=(new Date().getMonth()>=11 && new Date().getDate()>25)? currentyear+1 : currentyear
var christmas=new cdtime("caon-down", future_date)
christmas.displaycountdown("days", formatresults2)
</script>

Add active class on click using javascript

<script>
function act()
{
var selector, elems, makeActive;

selector = '.nav li';

elems = document.querySelectorAll(selector);

makeActive = function () {
    for (var i = 0; i < elems.length; i++)
        elems[i].classList.remove('active');

    this.classList.add('active');
};

for (var i = 0; i < elems.length; i++)
    elems[i].addEventListener('mousedown', makeActive);
}
</script>

<ul class="nav">
        <li onclick="act();"><a href="#intro" title="Next Section">a</a></li>
        <li onclick="act();"><a href="#second" title="Next Section">b</a></li>
        <li onclick="act();"><a href="#third" title="Next Section">c</a></li>
       <!-- <li><a href="#fifth" title="Next Section"><img src="slid/images/dot.png" alt="Link" /></a></li> -->
   
    </ul>

Add active class on scrolling using jQuery

$(window).scroll(function() {

    if ($(this).scrollTop() >= $('#intro').offset().top) {
       $('#nav #a1').addClass('active');
       $('#nav #a2').removeClass('active');
       $('#nav #a3').removeClass('active');
    }

    if ($(this).scrollTop() >= $('#second').offset().top) {
      $('#nav #a1').removeClass('active');
      $('#nav #a2').addClass('active');
      $('#nav #a3').removeClass('active');
    }
     if ($(this).scrollTop() >= $('#third').offset().top) {
      $('#nav #a2').removeClass('active');
      $('#nav #a3').addClass('active');
    }