Link menu for horizontal scrolling(added slide functionality)

HTML

<div id="links"><a id="0" href="javascript:void(0)">home </a> &nbsp; <a id="1" href="javascript:void(0)">about </a> &nbsp; <a id="2" href="javascript:void(0)">contact </a> &nbsp; <a id="3" href="javascript:void(0)">projects </a></div>
<div class="color 1" style="background-color:red;"></div>
<div class="color 2" style="background-color:blue;"></div>
<div class="color 3" style="background-color:green;"></div>
<div class="color 4" style="background-color:orange;"></div>

CSS

html{
    width:100%;
    height:100%;
    overflow-x:hidden;
}
body{
    width:100%;
    height:100%;
    overflow-x:hidden;
}
#links{
    position:fixed;
    bottom:30px;
    right:30px;
    z-index:100;
}
#links a{
    color:white;
}

#parent{
    height: 100%;
    overflow: auto;
}
.color{
    display:inline-block;
    height:100%;
}

JavaScript

var total=$(window).width()*4;
$('.color').css({'width':''+$(window).width()+''});
$('.1').css({'position':'absolute','left':'0px'});
$('.2').css({'position':'absolute','left':''+$(window).width()+'px'});
$('.3').css({'position':'absolute','left':''+$(window).width()*2+'px'});
$('.4').css({'position':'absolute','left':''+$(window).width()*3+'px'});


$('a').click(function(){
    var num=$(this).attr('id');
    $('html').animate({'scrollLeft':''+$(window).width()*num+''});//For mozilla
    $('body').animate({'scrollLeft':''+$(window).width()*num+''});//For other browsers
});

var downX;

$('body').mousedown(function(event){
   downX=event.clientX;
});
$('body').mouseup(function(event){
    var s=$('html').scrollLeft();
    var p=$('body').scrollLeft();
    
    var upX=event.clientX;
    var diff=downX-upX;
    if(diff<0)
    {
  $('html').animate({'scrollLeft':''+s-$(window).width()+''});//For mozilla
  $('body').animate({'scrollLeft':''+p-$(window).width()+''});//For other browsers
    }
    if(diff>0)
    {
        var g=s+$(window).width();
        var k=p+$(window).width();
  $('html').animate({'scrollLeft':''+g+''});//For mozilla
  $('body').animate({'scrollLeft':''+k+''});//For other browsers
    }
});