How can I make my js slider move the opposite direction?

Question

I'm trying to make my slider move in the opposite direction, but I can't figure out how to make it move right to left, instead it's moving left to right. I can get it to go right to left, but the problem I'm encountering is with the right to left movement, it doesn't stay a full grid, instead their is a mysterious gap between the two. With the left to right method, the grid moves as one huge block without any interruptions.

How can I make it so that my slider goes right to left and stops at the last li, and only go back with left arrow instead of doing a full wrap around by just pressing right/button?

http://jsfiddle.net/YDSWA/2/ (use arrow keys right and left to move slider)

Below is the jS for my slider and the jsFiddle has the CSS and HTML.

jQuery(document).ready(function ($) {
    var slideCount = $('#slider ul li').length;
    var slideWidth = $('#slider ul li').width();
    var slideHeight = $('#slider ul li').height();
    var sliderUlWidth = slideCount * slideWidth;
    $('#slider').css({
        width: slideWidth,
        height: slideHeight
    });
    $('#slider ul').css({
        width: sliderUlWidth,
        marginLeft: -slideWidth
    });
    $('#slider ul li:last-child').prependTo('#slider ul');
    function moveLeft() {
        $('#slider ul').animate({
            right: -slideWidth
        }, 700, function () {
            $('#slider ul li').prependTo('#slider ul');
            $('#slider ul').css('right', '');
        })
    }
    function moveRight() {
        $('#slider ul').animate({
            right: -slideWidth
        }, 700, function () {
            $('#slider ul li:first-child').appendTo('#slider ul');
            $('#slider ul').css('right', '');
        })
    }
    $('#back').click(function () {
        moveLeft();
    })
    $('#next').click(function () {
        moveRight();
    })

    $(document).keydown(function (e) {
        if (e.keyCode == 39) {
            moveRight();
        } else {

        }
    })
    $(document).keydown(function (e) {
        if (e.keyCode == 37) {
            moveLeft();
        } else {
        }
    })
});

Thanks for the help!

Answer 1

LIVE DEMO

jQ:

jQuery(function($) {

    var $sl = $('#slider'),
        $ul = $('ul', $sl),
        $li = $('li', $ul),
        slideCount  = $li.length,
        slideWidth  = $li.width(),
        slideHeight = $li.height(),
        sliderUlWidth = slideCount * slideWidth;

    $sl.css({width: slideWidth, height: slideHeight});
    $ul.css({width: sliderUlWidth});

    function moveLeft() {
      $ul.not(':animated').prepend( $('li:last-child', $ul) )
      .css({left:-slideWidth})
      .animate({left:0}, 700);
    }
    function moveRight() {
        $ul.not(':animated').animate({left: -slideWidth}, 700, function() {
          $(this).css({left: 0}).append( $('li:first-child', this) );
        });
    }

    $('#back, #next').click(function() {
        return this.id=='next' ? moveRight() : moveLeft();
    });

    $(document).keydown(function(e) {
        var k = e.which;
        if( k==39 || k==37 ){
            e.preventDefault();
            return k==39? moveRight() : moveLeft();  
        }
    });

});

CSS:

*{margin:0;padding:0;}
.uni_con {
    margin: 0 auto;
    width: 1200px;
}
#slider {
    position: relative;
    overflow: hidden;
    margin: 0 auto;
    background:#cf5;
}
#slider ul {
    position: relative;
    left:0;
    list-style: none;
    background:#f00;
}
#slider ul li {
    float: left;
    background: none;
    width: 1200px;
    background:#555;
    display: inline;
    position: relative;
}
#slider img {
    cursor: pointer;
    float:left;
    height: 400px;
    width: 400px;
}