jQuery Slide not Looping Back

Question

I found this simple Slideshow on the Internet, but the problem is that it doesn't repeat itself.

What I mean, is that it goes from 1 to 2, but doesn't go back to 1. What do I have to modify in the jQuery? Thanks, this is my first post.

JavaScript Code:

function slideSwitch() {
var mylenght = 5;
var $active = $('#slideshow IMG.active');

if ( $active.length == 0 ) $active = $('#slideshow IMG:last');
if ($active.length == mylenght) $active = $("#slideshow IMG:first")
// use this to pull the images in the order they appear in the markup
var $next =  $active.next().length ? $active.next()
    : $('#slideshow IMG:first');

// uncomment the 3 lines below to pull the images in random order

// var $sibs  = $active.siblings();
// var rndNum = Math.floor(Math.random() * $sibs.length );
// var $next  = $( $sibs[ rndNum ] );

$active.addClass('last-active');

$next.css({opacity: 0.0})
    .addClass('active')
    .animate({opacity: 1.0}, 1000, function() {
        $active.removeClass('active last-active');
    });
}

$(function() {
    setInterval( "slideSwitch()", 5000 );
});

Answer 1

Try this,

function slideSwitch() {
    var mylenght = 4;
    var $active = $('#slideshow IMG.active');

    if ($('#slideshow IMG').index($active) == mylenght - 1) 
        $next = $("#slideshow IMG:first")
    else
        $next = $active.next();


    $next.addClass('active').css({opacity: 0.0}).animate({opacity: 1.0}, 1000); 
    $active.removeClass('active').css({opacity: 1.0}).animate({opacity: 0}, 1000);
}

Have a look here http://jsfiddle.net/iamrmin/K62DX/